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Birth Settings in America: Outcomes, Quality, Access, and Choice (2020)

Chapter: 6 Maternal and Newborn Outcomes by Birth Setting

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Suggested Citation:"6 Maternal and Newborn Outcomes by Birth Setting." National Academies of Sciences, Engineering, and Medicine. 2020. Birth Settings in America: Outcomes, Quality, Access, and Choice. Washington, DC: The National Academies Press. doi: 10.17226/25636.
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Suggested Citation:"6 Maternal and Newborn Outcomes by Birth Setting." National Academies of Sciences, Engineering, and Medicine. 2020. Birth Settings in America: Outcomes, Quality, Access, and Choice. Washington, DC: The National Academies Press. doi: 10.17226/25636.
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Suggested Citation:"6 Maternal and Newborn Outcomes by Birth Setting." National Academies of Sciences, Engineering, and Medicine. 2020. Birth Settings in America: Outcomes, Quality, Access, and Choice. Washington, DC: The National Academies Press. doi: 10.17226/25636.
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Suggested Citation:"6 Maternal and Newborn Outcomes by Birth Setting." National Academies of Sciences, Engineering, and Medicine. 2020. Birth Settings in America: Outcomes, Quality, Access, and Choice. Washington, DC: The National Academies Press. doi: 10.17226/25636.
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Suggested Citation:"6 Maternal and Newborn Outcomes by Birth Setting." National Academies of Sciences, Engineering, and Medicine. 2020. Birth Settings in America: Outcomes, Quality, Access, and Choice. Washington, DC: The National Academies Press. doi: 10.17226/25636.
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Suggested Citation:"6 Maternal and Newborn Outcomes by Birth Setting." National Academies of Sciences, Engineering, and Medicine. 2020. Birth Settings in America: Outcomes, Quality, Access, and Choice. Washington, DC: The National Academies Press. doi: 10.17226/25636.
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Suggested Citation:"6 Maternal and Newborn Outcomes by Birth Setting." National Academies of Sciences, Engineering, and Medicine. 2020. Birth Settings in America: Outcomes, Quality, Access, and Choice. Washington, DC: The National Academies Press. doi: 10.17226/25636.
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Suggested Citation:"6 Maternal and Newborn Outcomes by Birth Setting." National Academies of Sciences, Engineering, and Medicine. 2020. Birth Settings in America: Outcomes, Quality, Access, and Choice. Washington, DC: The National Academies Press. doi: 10.17226/25636.
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Suggested Citation:"6 Maternal and Newborn Outcomes by Birth Setting." National Academies of Sciences, Engineering, and Medicine. 2020. Birth Settings in America: Outcomes, Quality, Access, and Choice. Washington, DC: The National Academies Press. doi: 10.17226/25636.
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Suggested Citation:"6 Maternal and Newborn Outcomes by Birth Setting." National Academies of Sciences, Engineering, and Medicine. 2020. Birth Settings in America: Outcomes, Quality, Access, and Choice. Washington, DC: The National Academies Press. doi: 10.17226/25636.
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Suggested Citation:"6 Maternal and Newborn Outcomes by Birth Setting." National Academies of Sciences, Engineering, and Medicine. 2020. Birth Settings in America: Outcomes, Quality, Access, and Choice. Washington, DC: The National Academies Press. doi: 10.17226/25636.
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Suggested Citation:"6 Maternal and Newborn Outcomes by Birth Setting." National Academies of Sciences, Engineering, and Medicine. 2020. Birth Settings in America: Outcomes, Quality, Access, and Choice. Washington, DC: The National Academies Press. doi: 10.17226/25636.
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Suggested Citation:"6 Maternal and Newborn Outcomes by Birth Setting." National Academies of Sciences, Engineering, and Medicine. 2020. Birth Settings in America: Outcomes, Quality, Access, and Choice. Washington, DC: The National Academies Press. doi: 10.17226/25636.
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Suggested Citation:"6 Maternal and Newborn Outcomes by Birth Setting." National Academies of Sciences, Engineering, and Medicine. 2020. Birth Settings in America: Outcomes, Quality, Access, and Choice. Washington, DC: The National Academies Press. doi: 10.17226/25636.
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Suggested Citation:"6 Maternal and Newborn Outcomes by Birth Setting." National Academies of Sciences, Engineering, and Medicine. 2020. Birth Settings in America: Outcomes, Quality, Access, and Choice. Washington, DC: The National Academies Press. doi: 10.17226/25636.
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Suggested Citation:"6 Maternal and Newborn Outcomes by Birth Setting." National Academies of Sciences, Engineering, and Medicine. 2020. Birth Settings in America: Outcomes, Quality, Access, and Choice. Washington, DC: The National Academies Press. doi: 10.17226/25636.
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Suggested Citation:"6 Maternal and Newborn Outcomes by Birth Setting." National Academies of Sciences, Engineering, and Medicine. 2020. Birth Settings in America: Outcomes, Quality, Access, and Choice. Washington, DC: The National Academies Press. doi: 10.17226/25636.
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Suggested Citation:"6 Maternal and Newborn Outcomes by Birth Setting." National Academies of Sciences, Engineering, and Medicine. 2020. Birth Settings in America: Outcomes, Quality, Access, and Choice. Washington, DC: The National Academies Press. doi: 10.17226/25636.
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Suggested Citation:"6 Maternal and Newborn Outcomes by Birth Setting." National Academies of Sciences, Engineering, and Medicine. 2020. Birth Settings in America: Outcomes, Quality, Access, and Choice. Washington, DC: The National Academies Press. doi: 10.17226/25636.
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Suggested Citation:"6 Maternal and Newborn Outcomes by Birth Setting." National Academies of Sciences, Engineering, and Medicine. 2020. Birth Settings in America: Outcomes, Quality, Access, and Choice. Washington, DC: The National Academies Press. doi: 10.17226/25636.
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Suggested Citation:"6 Maternal and Newborn Outcomes by Birth Setting." National Academies of Sciences, Engineering, and Medicine. 2020. Birth Settings in America: Outcomes, Quality, Access, and Choice. Washington, DC: The National Academies Press. doi: 10.17226/25636.
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Suggested Citation:"6 Maternal and Newborn Outcomes by Birth Setting." National Academies of Sciences, Engineering, and Medicine. 2020. Birth Settings in America: Outcomes, Quality, Access, and Choice. Washington, DC: The National Academies Press. doi: 10.17226/25636.
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Suggested Citation:"6 Maternal and Newborn Outcomes by Birth Setting." National Academies of Sciences, Engineering, and Medicine. 2020. Birth Settings in America: Outcomes, Quality, Access, and Choice. Washington, DC: The National Academies Press. doi: 10.17226/25636.
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Suggested Citation:"6 Maternal and Newborn Outcomes by Birth Setting." National Academies of Sciences, Engineering, and Medicine. 2020. Birth Settings in America: Outcomes, Quality, Access, and Choice. Washington, DC: The National Academies Press. doi: 10.17226/25636.
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Suggested Citation:"6 Maternal and Newborn Outcomes by Birth Setting." National Academies of Sciences, Engineering, and Medicine. 2020. Birth Settings in America: Outcomes, Quality, Access, and Choice. Washington, DC: The National Academies Press. doi: 10.17226/25636.
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Suggested Citation:"6 Maternal and Newborn Outcomes by Birth Setting." National Academies of Sciences, Engineering, and Medicine. 2020. Birth Settings in America: Outcomes, Quality, Access, and Choice. Washington, DC: The National Academies Press. doi: 10.17226/25636.
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Suggested Citation:"6 Maternal and Newborn Outcomes by Birth Setting." National Academies of Sciences, Engineering, and Medicine. 2020. Birth Settings in America: Outcomes, Quality, Access, and Choice. Washington, DC: The National Academies Press. doi: 10.17226/25636.
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Suggested Citation:"6 Maternal and Newborn Outcomes by Birth Setting." National Academies of Sciences, Engineering, and Medicine. 2020. Birth Settings in America: Outcomes, Quality, Access, and Choice. Washington, DC: The National Academies Press. doi: 10.17226/25636.
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Suggested Citation:"6 Maternal and Newborn Outcomes by Birth Setting." National Academies of Sciences, Engineering, and Medicine. 2020. Birth Settings in America: Outcomes, Quality, Access, and Choice. Washington, DC: The National Academies Press. doi: 10.17226/25636.
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Suggested Citation:"6 Maternal and Newborn Outcomes by Birth Setting." National Academies of Sciences, Engineering, and Medicine. 2020. Birth Settings in America: Outcomes, Quality, Access, and Choice. Washington, DC: The National Academies Press. doi: 10.17226/25636.
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Suggested Citation:"6 Maternal and Newborn Outcomes by Birth Setting." National Academies of Sciences, Engineering, and Medicine. 2020. Birth Settings in America: Outcomes, Quality, Access, and Choice. Washington, DC: The National Academies Press. doi: 10.17226/25636.
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Suggested Citation:"6 Maternal and Newborn Outcomes by Birth Setting." National Academies of Sciences, Engineering, and Medicine. 2020. Birth Settings in America: Outcomes, Quality, Access, and Choice. Washington, DC: The National Academies Press. doi: 10.17226/25636.
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Suggested Citation:"6 Maternal and Newborn Outcomes by Birth Setting." National Academies of Sciences, Engineering, and Medicine. 2020. Birth Settings in America: Outcomes, Quality, Access, and Choice. Washington, DC: The National Academies Press. doi: 10.17226/25636.
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Suggested Citation:"6 Maternal and Newborn Outcomes by Birth Setting." National Academies of Sciences, Engineering, and Medicine. 2020. Birth Settings in America: Outcomes, Quality, Access, and Choice. Washington, DC: The National Academies Press. doi: 10.17226/25636.
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Suggested Citation:"6 Maternal and Newborn Outcomes by Birth Setting." National Academies of Sciences, Engineering, and Medicine. 2020. Birth Settings in America: Outcomes, Quality, Access, and Choice. Washington, DC: The National Academies Press. doi: 10.17226/25636.
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Suggested Citation:"6 Maternal and Newborn Outcomes by Birth Setting." National Academies of Sciences, Engineering, and Medicine. 2020. Birth Settings in America: Outcomes, Quality, Access, and Choice. Washington, DC: The National Academies Press. doi: 10.17226/25636.
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Suggested Citation:"6 Maternal and Newborn Outcomes by Birth Setting." National Academies of Sciences, Engineering, and Medicine. 2020. Birth Settings in America: Outcomes, Quality, Access, and Choice. Washington, DC: The National Academies Press. doi: 10.17226/25636.
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Suggested Citation:"6 Maternal and Newborn Outcomes by Birth Setting." National Academies of Sciences, Engineering, and Medicine. 2020. Birth Settings in America: Outcomes, Quality, Access, and Choice. Washington, DC: The National Academies Press. doi: 10.17226/25636.
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PREPUBLICATION COPY, UNCORRECTED PROOFS 6 Maternal and Newborn Outcomes by Birth Setting The previous chapter describes the challenges involved in studying the effects of birth settings on maternal and neonatal outcomes in the United States. In addition to the deficiencies in data sources and methodological limitations discussed in that chapter, the literature on birth settings compares a wide array of beneficial and nonbeneficial outcomes across and within settings. Often these studies do not report the same outcomes or use the same definitions or terminology, making it difficult to develop assessments or to draw useful conclusions across the existing body of literature (Khan, 2019). In addition, the overall small number of U.S. women giving birth in home and birth center settings (under 2%) compared with hospital settings (about 98%) complicates many studies of outcomes by setting (MacDorman and Declercq, 2019). The reason is that infrequent events such as maternal and infant death, while of great interest to the committee, tend to have unstable estimates with wide confidence intervals as a result of relatively small sample sizes for home and birth center subgroups. Aspects of care during the childbearing year are also variable and dependent on such factors as the health of the mother and infant, models of prenatal and intrapartum care, the type of birth attendant, practice standards, and facility policies across and within birth settings and regions. Furthermore, as discussed in Chapter 2, the definition of what constitutes a birth center varies across the literature, both nationally and internationally, and most U.S. data sources cannot reliably track movement across birth settings or accurately attribute outcomes to the intended provider or place of birth (i.e., an intention-to-treat model). Where possible, the committee differentiates between outcomes for home births and outcomes for birth center births; however, some studies combine these births as “planned, out-of-hospital births” for analysis, which makes it impossible to compare the two (see, e.g., Snowden et al., 2015; Bovbjerg et al., 2017). With these caveats in mind, this chapter provides a framework for understanding outcomes by birth setting and reviews the available research on maternal and newborn health outcomes for low-risk women for all three U.S. birth settings—home, birth center, and hospital—as well as data on outcomes by provider type where available. It then reviews studies of outcomes by birth setting internationally. Finally, the chapter concludes with a discussion of how interprofessional collaboration influences outcomes across and within birth settings. Where possible, we highlight the broad spectrum of outcomes that are of interest for this report and point to gaps in data and understanding that need to be filled by further research. Importantly, we note that the literature reviewed focuses on outcomes by birth setting for low-risk women. As discussed in Chapter 3, maternal or fetal condition may have a significant 6-1

PREPUBLICATION COPY, UNCORRECTED PROOFS influence on the choice of birth setting, as women who have medical or obstetric risk factors or comorbidities or are pregnant with fetuses at risk for complications are likely to give birth in a hospital. Conversely, healthy low-risk women living in regions with access to home and birth center birth will be overrepresented in these settings. In the same way, hospital level will influence the sample studied; for example, very high-risk women and fetuses are overrepresented in tertiary care facilities. These differences make direct comparisons across settings difficult. In the absence of adequate data to control for risk level and demographic differences, accurate comparisons are impossible. UNDERSTANDING MATERNAL AND INFANT OUTCOMES Miller and colleagues (2016) describe a continuum of global maternity care wherein two patterns result in excess of morbidity and mortality. The authors refer to these extremes as “too little, too late” (TLTL) and “too much, too soon” (TMTS). TLTL is used to describe care in which inadequate staffing, training, infrastructure, supplies, and medications (Austin et al., 2014, p. 2,176) result in care that is withheld, below an evidence-based standard, or simply unavailable until it is too late. Severe morbidity and mortality result from this pattern of care. The converse system, TMTS, is characterized by routine overuse of interventions and the medicalization of healthy, uncomplicated pregnancies and births. Miller and colleagues (2016) argue that TMTS care often includes the unnecessary use of non–evidence-based interventions (e.g., continuous electronic fetal monitoring), as well as the overuse of interventions that can be life-saving but are potentially harmful when applied routinely, without medical indication (e.g., cesarean section). In these systems, overintervention drives morbidity. As facility births have increased globally, so has the recognition that TMTS systems can produce harm, increase costs, and concentrate disrespect and abuse in childbirth (Freedman and Kruk, 2014; World Health Organization, 2014; International Confederation of Midwives, White Ribbon Alliance, International Pediatric Association, and World Health Organization, 2015; Miller and Lalonde, 2015). While TMTS systems are typically associated with high-resource nations and TLTL with low- and middle- resource ones, because of inequality, these extremes often coexist within a single nation as a result of inequality. When preventable maternal (or fetal) death and severe morbidity occur in U.S. hospitals, these outcomes may result either from TMTS (as in the case of morbidity associated with higher- than-ideal cesarean rates) or from TLTL (as with unrecognized hemorrhage). When preventable death and suffering occur at home or in birth centers, these outcomes are likely the result of TLTL. In its review of the literature, the committee identified a number of maternal and infant outcomes of interest related to these TMTS and TLTL concepts. These outcomes include maternal and infant mortality and morbidity indicators, which have been the traditional focus of birth settings research, as well as psychosocial outcomes, including several measures of dignity in the childbirth process, such as bodily autonomy, maternal agency, respectful care, and empowerment. The committee chose to review as many of these outcomes as possible because, taken together, they provide a broader understanding of what “safety” and a “healthy mother, healthy baby, and healthy family” mean to childbearing families and to members of the care team. In short, this broader perspective recognizes that the experience of care cannot be separated from clinical outcomes; it is not a complement or secondary consideration, but an important aspect of ensuring high-quality childbirth care (World Health Organization, 2018). Moreover, the experience of care and the outcome of care are closely associated. Although the 6-2

PREPUBLICATION COPY, UNCORRECTED PROOFS committee recognizes the importance of patient experience in childbirth care, the literature on women’s experiences in the maternity care system is limited. That literature is discussed in detail below. Thus, in the discussion that follows, we examine the relationship between what we are calling intervention-related morbidity and birth setting, including outcomes and interventions reported in the literature, such as infection, induction, augmentation, postpartum hemorrhage, and genital tract tearing. We recognize that some of these interventions are necessary, unavoidable regardless of setting, or the result of maternal request. Nonetheless, because the desire to avoid unnecessary interventions is a primary reason families choose home and birth center births and because lower rates of these morbidities are also desirable from cost savings and quality-of-care perspectives, we review them in detail below. These morbidity outcomes are widely reported in the field, and thus are the focus of our review. However, we wish to emphasize that a broader conception of maternal morbidity is warranted. A more comprehensive view of morbidity would acknowledge the experiences of women and encompass such disorders as postpartum depression and anxiety, disrespect, unconsented care, coercion, and other forms of mistreatment that are starting to be documented in the United States (Vedam et al., 2019). These experiences impact not only the health of the person following childbirth but also that of the infant and family. Additionally, the literature on health outcomes by birth setting would benefit from disaggregation of outcomes by race/ethnicity, socioeconomic status, and sexual orientation and gender identity, where possible. While the current literature on outcomes largely does not address differences by race/ethnicity or other subpopulations, as noted in Chapters 3 and 4, traditionally marginalized groups often accrue a disproportionate share of clinical and social risk factors for adverse outcomes during pregnancy and birth. In the sections below, we report variations in outcomes by subpopulations where available, but underscore the general paucity of evidence in this area and the need for future research to grapple with potential variation in outcomes by subpopulations, particularly for historically marginalized groups. Given the difficulty of studying outcomes by birth setting for the reasons outlined above, as well as the tendency toward confirmatory bias noted by Roome and colleagues (2016),1 the committee, whose membership is diverse professionally, grappled with multiple tensions. Ultimately, we believe this was a strength because it led us to better understand multiple perspectives and viewpoints in a way that reflects the wide range of views and preferences held by U.S. women regarding place of birth. In general, we concluded that each setting—home, birth center, and hospital—offers a set of risks and benefits that accrue to either the pregnant woman or the newborn. And while no setting can fully remove risk from birth, evidence suggests that many risks are modifiable at the level of systems, processes, providers, and policies. 1 Roome and colleagues (2016) reviewed the position statements on home birth for midwifery and obstetric colleges in the United States, the United Kingdom, Canada, Australia, and New Zealand in an effort to examine how the same body of research tends to lead to different positions on the acceptability of birth in the home setting. They found that midwifery organizations tend to support home birth as a viable option for healthy women, whereas physicians’ organizations have statements that oppose this option. In 2015, the United Kingdom was the only country reviewed where physician- and midwife-led organizations had issued a joint statement in support of home birth. Roome and colleagues found widely differing stances that they argue reflect traditional midwifery perspectives on childbirth as a physiologic process versus obstetric perspectives, which focus on the potential for pathology. Ultimately, these authors assert that the differences in position statements are largely the by-product of confirmatory bias (i.e., the tendency to process information by looking for, or interpreting, information that is consistent with one’s existing beliefs). 6-3

PREPUBLICATION COPY, UNCORRECTED PROOFS FETAL AND NEONATAL OUTCOMES BY U.S. BIRTH SETTING Neonatal outcomes include neonatal mortality and neonatal morbidity. Death before delivery of the fetus is termed an intrapartum death. Death after birth is termed early neonatal mortality (up to 7 days of life).2 Death up to 28 days is termed neonatal mortality; death 29 days to 1 year of age, postneonatal mortality; and death up to 1 year of age, infant mortality. The majority of infant deaths occur during the first 7 days of life. This terminology is important as different studies refer to various timepoints and apply the term perinatal mortality inconsistently. Measures of neonatal morbidity include seizures, neonatal intensive care unit (NICU) admissions, hypoxic-ischemic encephalopathy, and low Apgar scores. The rates of neonatal mortality and morbidity across settings vary depending on the population studied and the parameters set by the researchers (e.g., whether researchers excluded congenital anomalies, or restricted the population to low-risk mothers). As discussed in Chapter 3, unforeseen emergencies related to either the birth process or an unrecognized condition of the newborn may require immediate skilled intervention, including cesarean delivery or neonatal resuscitation. In these cases, the ability to access higher-level care without delay is critical for the safety of the fetus or newborn. Risk for the newborn in a home or birth center birth setting and in hospitals without these capabilities may be mitigated through various strategies, including selection of low-risk mothers; referral to an obstetric or maternal- fetal medicine provider for pregnancy complications; minimization of transfer times in case of a need to transfer; barrier-free transfer to a hospital for birth complications; collaborative professional models of care; formal training of skilled practitioners; and professional regulation, oversight, and accountability (see Chapter 7). Several studies of health outcomes for newborns in home and birth center settings have been conducted in the United States. Hospital births attended by midwives are generally used as the baseline against which these birth settings are compared, and some studies report comparisons by provider type across and within setting as well. U.S. studies use registry and birth certificate data. The findings from these studies are shown in Tables 6-1 and 6-2. 2 Causes of death in this group refer to failure to resuscitate or consequences of severe hypoxic ischemic encephalopathy (see Chapter 3). 6-4

PREPUBLICATION COPY, UNCORRECTED PROOFS TABLE 6-1 Rate and Percentage of Neonatal Mortality by U.S. Birth Setting Study Data Source/ Sample Size Inclusion/Exclusion Birth Setting Mortality % Mortality Rate per Criteria 1,000 Live Births Neonatal Mortality (neonatal death reported as 0 to 27 or 28 days) Bovbjerg et al., 2017 MANA 2.0 dataset (2004–2009) and 4.0 Planned home or birth Planned home and birth center - 1.98 (ResQu: high, dataset (2012–2014) center births births GRADE: low) 47,394 out-of- hospital births Grünebaum et al., CDC linked birth/ infant death dataset Singleton, vertex, term Hospital birth with midwife - 0.32 2014 (2006–2009) (≥37 weeks and weight (ResQu: low) 12,709,881 hospital physician of ≥2,500 g) without Hospital birth with MD - 0.55 1,096,555 hospital midwife congenital 39,523 freestanding birth center midwife malformations Freestanding birth center birth - 0.59 61,993 home midwife with midwife 28,119 home other Home midwife - 1.26 Home other - 1.87 Grünebaum et al., CDC linked birth/ infant death dataset Singleton, term (≥37 Hospital birth with CNM - 0.32 2016 (2006–2009) weeks), ≥2,500 g, (ResQu: low) 1,096,555 hospital CNM nonanomalous 18,389 home CNM Home birth with CNM - 1.00 43,604 home uncertified midwife Home birth with uncertified - 1.37 midwife Grünebaum et al., CDC linked birth/ infant death dataset Singleton, term (≥37 Hospital birth with midwife - 0.31 2017a (2009–2013) weeks), weight ≥2,500 g, (ResQu: low, 1,077,197 hospital midwife nonanomalous GRADE: fair) 11,779,659 hospital physician Hospital birth with MD - 0.51 98,815 intended home birth Home birth - 1.21 Grünebaum et al., CDC linked birth/ infant death dataset Hospital birth with CNM - 0.35 2017b (2008–2012) 6-5

PREPUBLICATION COPY, UNCORRECTED PROOFS (ResQu: low, 1,363,199 hospital midwife Singleton, term (≥37 Hospital birth with MD - 0.60 GRADE: poor) 14,447,355 hospital MD weeks), birth weight 95,657 home midwife ≥2,500 g Home birth with midwife - 1.28 Malloy, 2010 CDC linked birth/ infant death dataset Singleton, term (37–42 Hospital birth with CNM - 0.5 (2000–2004) weeks), vaginal births 1,237,129 hospital CNM births 17,389 hospital “other” midwife births Hospital birth with other midwife - 0.4 13,529 home CNM births 42,375 home Birth center birth with CNM - 0.6 “other” midwife births 25,319 birth center CNM births Home birth with CNM - 1.0 Home birth with other midwife - 1.8 Snowden et al., 2015 Oregon birth, infant death, and fetal death Singleton, term (≥37 Hospital birth 0.06 - (ResQu: high, certificates (2012–2013) weeks), cephalic, GRADE: good) 75,923 hospital birth nonanomalous 3,203 out-of-hospital births Planned home birth 0.05 - 601 planned out of hospital but birthed at hospital Planned birth center birth 0.24 - Thornton et al., 2017 AABC (2006–2011) Received prenatal care in Hospital birth 0.04 - (ResQu: high, 8,776 Planned birth center birth birth center, singleton, GRADE: poor) 2,527 planned hospital births ≥37 weeks, admitted in Birth center birth 0.03 - spontaneous labor Tilden et al., 2017 U.S. birth and death records (2007–2010) Single, term (≥37 Hospital 0.08 - (ResQu: high, 106,823 hospital births weeks), vertex, GRADE: fair) 3,147 out-of- hospital births nonanomolous, delivered by VBAC Out-of-hospital 0.13 - Early Neonatal Mortality (early neonatal death reported as 0 to 6, 7, or 8 days) 6-6

PREPUBLICATION COPY, UNCORRECTED PROOFS Bachilova et al., CDC linked birth/ infant death Planned home births, Planned home births - 1.5 2018 certificates (2011–2013) ≥34 weeks, (ResQu: High, 71,704 planned home births nonanomolous Grade: Poor) Cheyney et al., MANA 2.0 dataset (2004–2009) Planned home births not Planned home births - 0.88 2014a 16,924planned out-of-hospital births transferred to another (ResQu: high, provider prior to labor GRADE: Poor) Cox et al., 2015 MANA 2.0 dataset (2004–2009) Planned out-of-hospital VBAC out-of-hospital births - 0.95 (ResQu: High, 1,052 TOLAC planned out-of-hospital birth not transferred to GRADE: Poor) births another provider prior to 12,092 out-of-hospital births labor, multiparous women without a history Out-of-hospital births - 0.41 of cesarean delivery Early neonatal death by days not specified Grünebaum et al., CDC linked birth/ infant death dataset Singleton, vertex, term Hospital birth with midwife - 0.14 2014 (2006–2009) (≥37 weeks and weight (ResQu: low) 12,709,881 hospital physician of ≥2,500 g) without Hospital birth with MD - 0.29 1,096,555 hospital midwife congenital 39,523 freestanding birth center midwife malformations 61,993 home midwife Freestanding birth center birth - 0.46 28,119 home other with midwife Home midwife - 0.93 Home other - 1.65 Late Neonatal Mortality (late neonatal death reported as 7 to 27 days) Cheyney et al., MANA 2.0 dataset (2004–2009) Planned home births not Planned home birth - 0.41 2014a 16,924 planned out-of-hospital births transferred to another (ResQu: high, provider prior to labor GRADE: Poor) Cox et al., 2015 MANA 2.0 dataset (2004–2009) Planned out-of-hospital VBAC out-of-hospital births - 0.95 (ResQu: High, 1,052 TOLAC planned out-of-hospital birth not transferred to GRADE: Poor) births another provider prior to 12,092 out-of-hospital births labor, multiparous 6-7

PREPUBLICATION COPY, UNCORRECTED PROOFS women without a history Out-of-hospital births - 0.17 of cesarean delivery Late neonatal death by days not specified NOTE: AABC = American Association of Birth Centers; CDC = Centers for Disease Control and Prevention; CNM = certified nurse midwife; GRADE = Grading of Recommendations, Assessment, Development, and Evaluation; MANA = Midwives Alliance of North America; ResQu = Birth Place Research Quality; TOLAC = trial of labor after cesarean; VBAC = vaginal birth after cesarean. TABLE 6-2 Rate and Percentage of Neonatal Morbidity by U.S Birth Setting Study Data Source/ Sample Inclusion/Exclusion Birth Setting Outcome Morbidity Morbidity Size Criteria % Rate per 1,000 Live Births Bovbjerg et al., 2017 MANA 2.0 dataset Planned home or birth center Planned home and birth Apgar 5 min <4 0.5 - (ResQu: high, (2004–2009) and 4.0 births center births GRADE: low) dataset (2012–2014) 47,394 out-of-hospital Apgar 5 min <7 1.5 - births Neonatal hospitalization 7.4 - first 6 weeks NICU admission first 6 2.8 - weeks Cheng et al., 2013 CDC birth certificate Singleton, term (37-42 Hospital births Apgar 5 min <4 (ResQu: moderate) data (2008) weeks), vertex, planned birth Planned home births by Hospital birth 0.24 - 12,039 planned home center and home births CNM births Home birth CNM 0.19 - 2,069,714 planned Planned home births by Home birth other midwife 0.27 - hospital births other midwives Apgar 5 min <7 Hospital birth 1.17 - Home birth CNM 1.06 - Home birth other midwife 2.63 - Ventilator support >6 h 6-8

PREPUBLICATION COPY, UNCORRECTED PROOFS Hospital birth 0.27 - Home birth CNM 0.18 - Home birth other midwife 0.23 - NICU admissions Hospital birth 3.03 - Home birth CNM 0.37 - Home birth other midwife 0.64 - Cheyney et al, 2014a MANA 2.0 dataset Planned home births not Planned home births Apgar 5 min <7 (ResQu: high, (2004–2009) transferred to another GRADE: Poor) 16,924 planned out-of- provider prior to labor Planned home births 1.5 - hospital births NICU admission in the first 6 weeks Planned home births 2.8 - Cox et al., 2015 MANA 2.0 dataset Planned out-of-hospital birth TOLAC out-of-hospital Apgar 5 min <4 (ResQu: High, (2004–2009) not transferred to another births GRADE: Poor) 1,052 TOLAC planned provider prior to labor, TOLAC out-of-hospital 1.0 - out-of-hospital births multiparous women without Out-of-hospital births births 12,092 out-of-hospital a history of cesarean out-of-hospital births 0.4 - births delivery NICU admission TOLAC out-of-hospital 4.2 - births out-of-hospital births 2.0 - Infant hospitalization in first 6 weeks TOLAC out-of-hospital 17.0 - births out-of-hospital births 7.8 - Grünebaum et al., CDC birth certificate Singleton, term (≥37 weeks), Hospital MD Apgar 5 min = 0 2013 data (2007–2010) ≥2,500 g (ResQu: low) Hospital midwife Hospital MD - 0.16 6-9

PREPUBLICATION COPY, UNCORRECTED PROOFS 12,663,051 hospital Hospital midwife - 0.09 physician Freestanding birth center 1,118,578 hospital midwife Freestanding birth center - 0.55 midwife midwife 42,216 freestanding Home midwife Home midwife - 1.63 birth center midwife 67,429 home midwife Malloy, 2010 CDC linked birth/ Singleton, term (37–42 Hospital birth with CNM Apgar 5 min <4 infant death dataset weeks), vaginal births (2000–2004) Hospital birth with other Hospital birth CNM - 0.7 1,237,129 hospital midwife Hospital birth other - 0.6 CNM births midwife 17,389 hospital “other” Birth center birth with CNM Birth center birth CNM - 0.5 midwife births 13,529 home CNM Home birth with CNM Home birth CNM - 5.5 births Home birth other midwife - 2.3 42,375 home Home birth with other “other” midwife births midwife Injury at birth 25,319 birth center Hospital birth CNM - 3.1 CNM births Hospital birth other - 1.5 midwife Birth center birth CNM - 0.9 Home birth CNM - 2.4 Home birth other midwife - 1.7 Mechanical ventilation <30 min Hospital birth CNM - 15.1 Hospital birth other - 20.8 midwife Birth center birth CNM - 10.2 Home birth CNM - 10.8 Home birth other midwife - 15.6 Mechanical ventilation 30 min 6-10

PREPUBLICATION COPY, UNCORRECTED PROOFS Hospital birth CNM - 2.7 Hospital birth other - 2.6 midwife Birth center birth CNM - 1.4 Home birth CNM - 2.0 Home birth other midwife - 3.9 Snowden et al., 2015 Oregon birth, infant Singleton, term (≥37 weeks), Hospital birth Apgar 5 min <4 (ResQu: high, death, and fetal death cephalic, nonanomalous Planned home birth Hospital birth 0.4 - GRADE: good) certificates (2012– Planned birth center birth 2013) Planned home birth 0.3 - 75,923 hospital births Planned birth center birth 0.6 - 3,203 out-of-hospital births Apgar 5 min <7 601 planned out of Hospital birth 1.9 - hospital but birthed at hospital Planned home birth 1.2 - Planned birth center birth 2.5 - NICU admission Hospital birth 3.0 - Planned home birth 0.8 - Planned birth center birth 1.1 - Ventilation Hospital birth 3.3 - Planned home birth 2.5 - Planned birth center birth 4.5 - Thornton et al., 2017 AABC (2006-2011) Received prenatal care in Hospital birth Apgar 5 min <7 (ResQu: high, 8,776 Planned birth birth center, singleton, ≥37 Birth center birth Hospital birth 0.51 - GRADE: poor) center births weeks, admitted in 2,527 Planned hospital spontaneous labor Birth center birth 0.80 - births Neonatal composite Hospital birth 0.44 - Birth center birth 0.44 - 6-11

PREPUBLICATION COPY, UNCORRECTED PROOFS Newborn ventilation <10 min Hospital birth 2.26 - Birth center birth 3.05 - Tilden et al., 2017 U.S. birth and death Single, term (≥37 weeks), Hospital Apgar 5 min <4 (ResQu: high, records (2007–2010) vertex, nonanomolous, Out of hospital Hospital 0.4 GRADE: fair) 106,823 hospital births delivered by VBAC 3,147 out-of- hospital Out of hospital 0.73 births Apgar 5 min <7 Hospital 2.68 Out of hospital 4.42 Ventilator support Hospital 0.29 Out of hospital 0.38 NICU admission Hospital 3.10 Out of hospital 1.11 Birth injury Hospital 0.10 Out of hospital 0.03 NOTE: AABC = American Association of Birth Centers; CDC = Centers for Disease Control and Prevention; CNM = certified nurse midwife; GRADE = Grading of Recommendations, Assessment, Development, and Evaluation; MANA = Midwives Alliance of North America; NICU = neonatal intensive care unit; ResQu = Birth Place Research Quality; TOLAC = trial of labor after cesarian; VBAC = vaginal birth after cesarean. 6-12

PREPUBLICATION COPY, UNCORRECTED PROOFS Systematic Reviews Three important systematic reviews have examined neonatal outcomes for home and birth center settings as compared with hospital settings: Phillippi and colleagues (2018) and Wax and colleagues (2010). We discuss each study in detail below. Wax and colleagues (2010) published a systematic review of birth outcomes for planned home and hospital births, which included all English-language, peer-reviewed publications from high-resource countries available at the time that reported fetal and neonatal outcomes by birth setting. Neonatal outcomes for planned home births included lower rate of low birthweight (less than 10% for gestational age or less than 2,500 grams) (1.3% vs. 2.2%; odds ratio [OR] 0.60; confidence interval [CI] 0.50–0.71), compared with the hospital sample. The neonatal mortality rate was nearly twice as high in planned home births as compared with planned hospital births (0.20% vs. 0.09%; OR 1.98; CI 1.19–3.28), and nearly three times as high when only nonanomalous infants were included in the analysis (0.15% vs. 0.04%; OR 2.87; CI 1.32–6.25). It is important to note that when sensitivity analyses were performed, which removed older studies and excluded those that had used matching, there was no significant difference in prematurity and neonatal death between the two birth settings (Wax et al., 2010). Phillippi and colleagues (2018) conducted a systematic review of 17 studies on neonatal outcomes; all of the studies evaluated neonatal mortality, and some also evaluated neonatal morbidity. Collectively, the studies included outcomes for the neonates of a total of 84,500 women admitted to a birth center in labor, including outcomes after transfer. The review found that in no study with a hospital comparison group was there a higher rate of neonatal mortality in the birth center group, and that nulliparous women and women older than 35 had a higher risk of poor neonatal outcomes in both birth centers and hospitals. In any studies that included births with a gestation more than 42 weeks, a higher risk of neonatal mortality was found for those pregnancies (Phillippi et al., 2018). All of these studies demonstrated selection of a favorable medical, obstetric, and social risk profile among women choosing home and birth center settings. Birth Registry Studies A number of studies use birth registries, allowing for analysis on an intention-to-treat basis. As discussed in Chapter 4, however, they are limited in that reporting to registries is not mandatory. This means that findings come from samples rather than complete populations, and thus may not be generalizable. Moreover, because these studies are descriptive in nature, none have an explicit comparison group. Four descriptive studies using registry data—by Cox and colleagues (2015; 1.24/1,000 for women without a history of cesarean [ResQu: high, GRADE: poor]),3 Cheyney and colleagues (2014a; 0.85/1,000 [ResQu: high, GRADE: poor]),4 Johnson 3 The study by Cox and colleagues (2015), who used the same data registry, describes neonatal outcomes for women (n = 1,052) who planned a vaginal birth after cesarean (VBAC) at home with midwives who were contributing data to the Midwives Alliance of North America Statistics Project (MANA Stats) 2.0 data registry between 2004 and 2009. Five neonatal deaths (4.75/1,000) occurred in the prior cesarean group compared with 1.24/1,000 in multiparas without a history of cesarean (p = 0.015).  4 Cheyney and colleagues (2014a) found elevated rates of fetal intrapartum and neonatal mortality in a home birth sample (n = 16,924) when clients with higher-risk factors such as breech, twins, labor after cesarean section with no prior vaginal birth, gestational diabetes, and preeclampsia were included in the sample. Low Apgar scores 6-13

PREPUBLICATION COPY, UNCORRECTED PROOFS and Daviss (2005; 1–2/1,000 [ResQu: moderate, GRADE: poor]), and Stapleton and colleagues (2013; 0.47/1,000 [ResQu: high, GRADE: poor])—have documented low rates of perinatal mortality at home and in birth centers for healthy, low-risk women in the United States using birth registry data. Thornton and colleagues (2017 [ResQu: high, GRADE: poor]), similarly using registry data, compared midwife-led birth center and hospital groups and found no difference in the neonatal outcome composite5 (0.44% for both groups).6 Vital Statistics Studies A number of other frequently cited studies report fetal and neonatal outcomes by birth setting using vital statistics. In 2012, the state of Oregon added new variables to the birth certificate (intended place of birth and the type of intended provider at the onset of labor), allowing Snowden and colleagues (2015) to use an intention-to-treat approach to examine outcomes by birth setting. The authors limited analyses to data from Oregon collected over the 2- year period following the change to the birth certificate, yielding a sample of 75,923 hospital births and 3,203 home and birth center births. Looking at singleton, term, nonanomalous births, this study found poorer outcomes at home and in birth centers—specifically, a perinatal mortality rate of 3.9 per 1,000 in home birth and birth center births compared with 1.8 per 1,000 in hospital births, and a neonatal mortality rate of 1.6 per 1,000 in home birth and birth center births compared with 0.6 per 1,000 in hospital births (Snowden et al., 2015). Malloy (2010) conducted a retrospective cohort study measuring infant outcomes by setting and birth attendant using linked birth and death files from 2000 to 2004. The samples included hospital births attended by a certified nurse midwife (CNM), hospital births attended by another type of midwife, birth center birth attended by a CNM, home births attended by a CNM, and home births attended by another type of midwife. The neonatal mortality rate (measured as 0–27 days after birth) was 0.5/1,000 live births for hospital-CNM, 0.4/1,000 for hospital-other midwife, 0.6/1,000 for birth center-CNM, 1.0 for home-CNM, and 1.8/1,000 for home-other midwife. Births at home with a CNM or other midwife had a higher risk of neonatal death compared with hospital births with a CNM (2.02/1,000, CI 1.18–3.45; 3.63/1,000, CI 2.89–4.67, respectively). Home births attended by any midwife had a greater risk of a low 5-minute Apgar score <4 (home-CNM 7.83/1,000, CI: 6.09–10.1; home-other midwife 3.39/1,000, CI 2.70–4.24) compared with CNM-attended hospital deliveries. Other studies also used vital statistics data (see, e.g., Cheng et al., 20137 [ResQu: (<7) occurred in 1.5 percent of newborns, and postpartum neonatal transfers were infrequent, occurring in only 0.9 percent of births. In terms of postnatal outcomes, 86 percent of newborns were breastfeeding exclusively at 6 weeks of age. Excluding lethal anomalies, the intrapartum, early neonatal, and late neonatal mortality rates were 1.30, 0.41, and 0.35 per 1,000, respectively, when higher-risk births were included, for a combined perinatal death rate of 2.06 per 1,000. When the sample was limited to low-risk women (term, singleton, vertex, no previous cesarean), the intrapartum mortality rate dropped to 0.85/1,000. 5 The neonatal outcome composite consisted of severe prenatal outcomes: intrapartum and newborn mortality, hypoxic neurologic injury, Apgar score <4 at 5 minutes, seizures, persistent pulmonary hypertension, positive pressure ventilation >10 minutes, and meconium aspiration syndrome. 6 Thornton and colleagues (2017), using Perinatal Data Registry data, used exclusion criteria to form low- risk groups admitted to birth centers (n = 8,776) and those that chose hospital admission (n = 2,527). 7 The study by Cheng and colleagues (2013) used 2008 vital statistics data from 27 states, which included the 2003 revision of the birth certificate that delineates the location of a birth as hospital, freestanding birth center, or home, and further as accidental, intended, or unknown if intended. Although the 2003 revision of the birth 6-14

PREPUBLICATION COPY, UNCORRECTED PROOFS moderate]; Grünebaum et al., 2013,8 2014,9 2015b10 [ResQu: low]; Bachilova et al., 201811 [ResQu: low, GRADE: poor]; and Wasden et al., 201712 [ResQu: low]). Collectively, these certificate includes information about where the birth took place and the planned status of that birth, it does not take into account intention-to-treat. Thus, the data do not account, for example, for planned home births that were transferred to hospitals. The authors compared outcomes of neonates whose mothers had planned home births and those who delivered in hospitals, and found that, compared with hospital births, more planned home births had 5- minute Apgar scores below 4 and a lower rate of NICU admission; they do not report neonatal mortality. 8 In their 2013 study, Grünebaum and colleagues used birth certificate data from the CDC’s National Center for Health Statistics to examine deliveries by physicians and midwives in and out of the hospital between 2007 and 2010 for a national sample of nearly 14 million singleton term births. Term was defined as 37 weeks or more gestation and a birthweight of 2,500 g or more. The majority of term singleton births (91%; n = 12,663,051) were physician-attended hospital births; midwife-attended hospital births constituted 8 percent of births (n = 1,118,678), 0.3 percent were midwife-led freestanding birth center births (n = 42,216), and 0.5 percent (n = 67,429) were midwife home deliveries. Grünebaum and colleagues (2013) found that, compared with hospital births attended by physicians or midwives, home births and births in freestanding birth centers attended by midwives had a significantly higher risk of a 5-minute Apgar score of 0 and neonatal seizures or serious neurologic dysfunction. This risk was greater for nulliparous women. In addition, women who gave birth at home with a midwife attending were significantly more likely to have macrosomic infants (birthweight greater than 4,000 g); see Tables 5-1 and 5- 2. The distinction between causality and correlation should be noted here. Birth settings would not cause higher birthweight, but home births could be correlated with higher birthweight for multiple reasons, such as waiting until the natural onset of labor rather than undergoing induction (see, e.g., Zhang et al., 2010). 9 The 2014 study by Grünebaum and colleagues used the CDC-linked birth and infant death dataset from 2006–2009 for early and total neonatal mortality for nearly 14 million singleton, vertex, and term births without congenital anomalies. This dataset included births attended by midwives and physicians in the hospital and midwives at home and in birth centers. The authors used midwife-attended home births as a proxy for planned home births. Compared with deliveries by hospital midwives, home births were more likely to be postterm, and mothers were more likely to have macrosomic infants. Midwife-attended home births also had a significantly higher total neonatal mortality risk relative to deliveries attended by midwives in the hospital, and the risk of neonatal mortality increased for postterm births and nulliparous women. Similar results were observed for early neonatal mortality. The excess total neonatal mortality for midwife-attended home births compared with midwife-attended hospital births was estimated at 0.93 per 1,000 births, and the excess early neonatal mortality at 0.79 per 1,000 births. In birth center births, excess total neonatal mortality was reported as .26 per 1,000 births, and excess early neonatal mortality as .32 per 1,000 births (Grünebaum, 2014). 10 The 2015 study by Grünebaum and colleagues used a national sample of about 12 million deliveries from 2010–2012 CDC-linked vital records to analyze the frequency of four perinatal risk factors—breech presentation, prior cesarean delivery, twins, and gestational age 41 weeks or longer—that were associated with planned midwife- attended home births in the United States, and compare them with deliveries performed in the hospital by CNMs. (Home births attended by others were excluded; only planned home births attended by midwives were included.) Compared with CNM-attended hospital births, all four risk factors were significantly higher among midwife- attended planned home births, and three were significantly higher for planned home births attended by midwives not certified by the American Midwifery Certification Board (AMCB). 11 The 2018 study by Bachilova and colleagues used CDC-linked vital records for 2011–2013 to conduct a 3-year retrospective cohort study of 71,704 planned home births in the United States. The authors found an overall early neonatal mortality rate of 1.5 per 1,000 planned home births, with significantly elevated risk in some subgroups. The risk of early neonatal death was significantly higher among nulliparous women (adjusted odds ratio [aOR] 2.71; 95% CI 1.71–4.31), women with previous cesarean births (aOR 2.62; 95% CI 1.25–5.52), nonvertex presentations (aOR 4.27; 95% CI 1.33–13.75), plural births (aOR 9.79; 95% CI 4.25–22.57), preterm births (34– <37 weeks gestation) (aOR 4.68; 95% CI 2.30–9.51), and births at ≥41 weeks gestation (aOR 1.76; 95% CI 1.09– 2.84). The authors conclude that early neonatal deaths occur more commonly when certain risk factors are present and that more careful patient selection may reduce adverse neonatal outcomes among planned home births. 12 Wasden and colleagues (2017) used vital statistics data from New York City as their control group to identify the risk of HIE (hypoxic ischemic encephalopathy) compared with infants who received head cooling for 6-15

PREPUBLICATION COPY, UNCORRECTED PROOFS authors found worse neonatal outcomes for completed home births, including higher rates of neonatal mortality (Grünebaum and colleagues only), low 5-minute Apgar scores, and neonatal seizures. However, these studies were unable to track outcomes using an intention-to-treat model, and the impact of misclassification on the reliability of findings from studies based on vital statistics has not been conclusively studied. Similarly, as discussed in Chapter 4, it is difficult to ensure that all of the home births in a study sample were planned and attended because of variability in birth certificates from state to state whereby some accidental home births cannot be distinguished from planned ones (California), and planned, unassisted home births (also called “freebirths”) cannot be readily distinguished from those that are attended by a trained midwife (all states). Comparative Risk of Neonatal Mortality and Morbidity U.S. studies show elevated rates of neonatal mortality in home births compared with hospital births; see Tables 6-3 and 6-4. The relative risk to the infant may be two-fold, with absolute risks of about 1.2/1,000 versus 0.6/1,000 for home and hospital, respectively. The literature is not conclusive as to the magnitude of these rates because the available data make it difficult to distinguish between planned and unplanned or accidental home births, attended and intentionally unassisted births (also called “freebirths”), and provider type, if present. Finding 6-1: Statistically significant increases in the relative risk of neonatal death in the home compared with the hospital setting have been reported in most U.S. studies of low- risk births using vital statistics data. However, the precise magnitude of the difference is difficult to assess given flaws in the underlying data. Regarding serious neonatal morbidity, studies report a wide range of risk for low-risk home versus hospital birth and by provider type. Given the importance of understanding these severe morbidities, the differing results among studies are of concern and require further study. Research is critically needed to further evaluate neonatal outcomes among home and freestanding birth centers. Vital statistics studies of freestanding birth center outcomes show an increased risk of poor neonatal outcomes. Studies conducted in the United States using an intention-to-treat approach have demonstrated that births in birth centers and hospitals have similar to slightly elevated rates of neonatal and perinatal mortality. Finding 6-2: Vital statistics studies of low-risk births in freestanding birth centers show an increased risk of poor neonatal outcomes, while studies conducted in the United States using models indicating intended place of birth have demonstrated that low-risk births in birth centers and hospitals have similar to elevated rates of HIE at a New York City institution. Demographics, obstetric information, location of birth, and intended location of birth were obtained from the vital records for both the cases and controls. A total of 69 infants underwent head cooling for HIE and were matched with 276 normal controls. After adjusting for pregnancy characteristics and mode of delivery, the odds of having an infant requiring treatment for HIE was 44 (95% CI 1.7–256.4) for out-of-hospital births compared with infants without HIE, regardless of intended place of birth. For those who did plan a home birth, the odds of having an infant with HIE were 21 (95% CI 1.7–256.4) compared with infants not requiring treatment for HIE. The authors conclude that out-of-hospital births were associated with increased odds of having an infant requiring treatment for HIE. 6-16

PREPUBLICATION COPY, UNCORRECTED PROOFS neonatal mortality. Findings of studies of the comparative risk of neonatal morbidity between low-risk birth center and hospital births are mixed, with variation across studies by outcome and provider type. Moreover, giving the interrelationship of midwife credentialing with birth settings, its mediating effect on perinatal outcomes cannot be ascertained with confidence from the current literature. 6-17

PREPUBLICATION COPY, UNCORRECTED PROOFS TABLE 6-3 Comparative Risk of Neonatal Mortality by Birth Setting Study Data Source/ Sample Size Inclusion/ Exclusion Type of birth RR (95% CI) Adj. OR (95% CI) Criteria Total Neonatal Mortality Grünebaum et al., CDC linked birth/infant death Singleton, vertex, term (≥ Hospital midwife (ref) 1 - 2014 dataset (2006–2009) 37 weeks and weight of ≥ (ResQu: low) 12,709,881 hospital physician 2,500 g) without Hospital MD 1.69 (1.52–1.88) - 1,096,555 hospital midwife congenital malformations Freestanding birth center midwife 1.81 (1.19–2.75) - 39,523 freestanding birth center Neonatal death reported as midwife 0–27 days Home midwife 3.87 (3.03–4.95) - 61,993 home midwife 28,119 home other Home other 5.75 (4.31–7.68) - Grünebaum et al., CDC linked birth/infant death Singleton, term (≥37 Hospital birth with CNM 0.33 (0.21–0.53) - 2016 dataset (2006–2009) weeks), ≥2,500 g, (ResQu: low) 1,096,555 hospital CNM nonanomalous Home birth with CNM (ref) 1 - 18,389 home CNM Neonatal death reported as 43,604 home uncertified midwife 0–27 days Home birth with uncertified midwife 1.41 (0.83–2.38) - Grünebaum et al., CDC linked birth/infant death Singleton, term (≥37 Hospital birth with CNM (ref) 1 - 2017b dataset (2008–2012) weeks), birthweight ≥ (ResQu: low, 1,363,199 hospital midwife 2,500 g Hospital birth with MD 1.71 (1.6–1.9) - GRADE: poor) 14,447,355 hospital MD 95,657 home midwife Home birth with midwife 3.62 (3–4.4) - Malloy, 2010 CDC linked birth/infant death Singleton, term (37–42 Hospital birth with CNM (ref) - 1.00 dataset (2000–2004) weeks), vaginal births 1,237,129 hospital CNM births Neonatal death reported as 17,389 in-hospital “other” midwife 0–27 days Hospital birth with other midwife - 0.79 (0.37–1.66) births 13,529 home CNM births Birth center birth with CNM - 1.54 (0.94–2.54) 42,375 home “other” midwife births 25,319 birthing center CNM births. Home birth with CNM - 2.02 (1.18–3.45) Home birth with other midwife - 3.63 (2.89–4.67) 6-18

PREPUBLICATION COPY, UNCORRECTED PROOFS Snowden et al., Oregon birth, infant death, and fetal Singleton, term (≥37 Hospital birth (ref) - 1 2015 death certificates (2012–2013) weeks), cephalic, (ResQu: high, 75,923 hospital births nonanomalous GRADE: good) 3,203 out-of-hospital births Neonatal death reported 601 planned out of hospital but as 0-28 days birthed at hospital Infant death after Out-of-hospital birth - 1.68 (0.77–3.66) reclassification of hospital transfers as planned out- of-hospital births Tilden et al., 2017 U.S. birth and death records (2007– Single, term (≥37 weeks), Hospital (ref) - 1 (ResQu: high, 2010) vertex, nonanomolous, GRADE: fair) 106,823 hospital births delivered by VBAC 3,147 out-of-hospital births Out-of-hospital - 2.10 (0.73–6.05) Early Neonatal Mortality Grünebaum et al., Singleton, vertex, term (≥ Hospital midwife (ref) 1 - 2014 37 weeks and weight of ≥ Hospital MD 2.04 (1.73–2.39) - (ResQu: low) 2,500 g) without congenital malformations Freestanding birth center midwife 3.26 (2.01–5.31) - Early neonatal death Home midwife 6.6 (4.88–8.93) - reported as 0–6 days Home other 11.73 (8.45–16.28) - NOTE: CDC = Centers for Disease Control and Prevention; CNM = certified nurse midwife; GRADE = Grading of Recommendations, Assessment, Development, and Evaluation; ResQu = Birth Place Research Quality; VBAC = vaginal birth after cesarean. TABLE 6-4 Comparative Risk of Neonatal Morbidity by Birth Setting Study Data Source/ Inclusion/Exclusion Criteria Birth Setting Outcome RR (95% CI) Adj. OR (95% CI) Sample Size Cheng et al., 2013 CDC birth certificate Singleton, term (37–42 weeks), Hospital births Apgar 5 min <4 (ResQu: moderate) data (2008) vertex, planned birth center Planned home births by 12,039 planned home and home births CNM Hospital birth (ref) - 1 births Home birth CNM - 0.69 (0.26–1.83) 2,069,714 planned Planned home births by hospital births other midwives Home birth other midwife - 1.62 (1.01–1.83) 6-19

PREPUBLICATION COPY, UNCORRECTED PROOFS Apgar 5 min <7 Hospital birth (ref) - 1 Home birth CNM - 0.77 (0.52–1.16) Home birth other midwife - 2.92 (2.49–3.42) Ventilator support >6 h Hospital birth (ref) - 1 Home birth CNM - 0.73 (0.33–1.63) Home birth other midwife - 0.91 (0.53–1.54) NICU admissions Hospital birth (ref) - 1 Home birth CNM - 0.13 (0.07–0.23) Home birth other midwife - 0.24 (0.18–0.34) Grünebaum et al., CDC birth certificate Singleton, term (≥37 weeks), Hospital MD Apgar 5 min = 0 2013 data (2007–2010) ≥2,500 g (ResQu: low) 12,663,051 hospital Hospital midwife Hospital MD (ref) 1 - physician 1,118,578 hospital Freestanding birth center Hospital midwife 0.55 (0.45–0.68) - midwife midwife 42,216 freestanding birth center midwife Home midwife Freestanding birth center 3.56 (2.36–5.36) - 67,429 home midwife midwife Home midwife 10.55 (8.62–12.93) - Malloy, 2010 CDC linked birth/ Singleton, term (37–42 weeks), Hospital birth with CNM Apgar 5 min <4 infant death dataset vaginal births Hospital birth CNM (ref) 1 - (2000–2004) Hospital birth with other 1,237,129 hospital midwife Hospital birth other midwife - 0.78 (0.42–1.46) CNM births Birth center birth CNM 0.80 (0.45–1.42) - 17,389 hospital Birth center birth with “other” midwife CNM Home birth CNM - 7.83 (6.09–10.1) births Home birth other midwife 3.39 (2.70–4.24) - 6-20

PREPUBLICATION COPY, UNCORRECTED PROOFS 13,529 home CNM Home birth with CNM Injury at birth births Hospital birth CNM (ref) - 1 42,375 home Home birth with other “other” midwife midwife Hospital birth other midwife - 0.47 (0.31–0.70) births Birth center birth CNM - 0.36 (0.23–0.55) 25,319 birthing center CNM births Home birth CNM - 0.84 (0.58–1.22) Home birth other midwife - 0.59 (0.46–0.76) Mechanical ventilation <30 min Hospital birth CNM (ref) - 1 Hospital birth other midwife - 1.33 (1.18–1.51) Birth center birth CNM - 0.79 (0.69–0.92 Home birth CNM - 0.74 (0.61–0.89) Home birth other midwife - 1.08 (0.98–1.18) Mechanical ventilation 30 min Hospital birth CNM (ref) - 1 Hospital birth other midwife - 0.98 (0.73–1.13) Birth center birth CNM - 0.66 (0.47–0.94) Home birth CNM - 0.83 (0.55–1.25) Home birth other midwife - 1.63 (1.38–1.94) Snowden et al., Oregon birth, infant Singleton, term (≥37 weeks), Hospital birth (ref) Apgar 5 min <4 2015 death, and fetal death cephalic, nonanomalous Out-of-hospital birth Hospital birth (ref) - 1 (ResQu: high, certificates (2012– Adjusted odds ratio after GRADE: good) 2013) reclassification of hospital Out-of-hospital birth - 1.56 (0.98–2.47) 75,923 hospital births transfers as planned out-of- Apgar 5 min <7 3,203 out-of-hospital hospital births Hospital birth (ref) - 1 births 601 planned out of Out-of-hospital birth - 1.31 (1.04–1.66) hospital but birthed NICU admission at hospital Hospital birth (ref) - 1 6-21

PREPUBLICATION COPY, UNCORRECTED PROOFS Out-of-hospital birth - 0.71 (0.55–0.92) Ventilation Hospital birth (ref) - 1 Out-of-hospital birth - 1.36 (1.14–1.62) Thornton et al., AABC (2006–2011) Received prenatal care in birth Hospital birth Apgar 5 min 3–7 2017 8,776 planned birth center, singleton, ≥37 weeks, Birth center birth Hospital birth (ref) - 1 (ResQu: high, center births admitted in spontaneous labor GRADE: poor) 2,527 planned Birth center birth - 1.51 (0.80–2.85) hospital births Neonatal composite Hospital birth (ref) - 1 Birth center birth - 1.13 (0.60–2.13) Newborn ventilation <10 min Hospital birth (ref) - 1 Birth center birth - 1.31 (0.97–1.79) Tilden et al., 2017 U.S. birth and death Single, term (≥37 weeks), Hospital Apgar 5 min <4 (ResQu: high, records (2007–2010) vertex, nonanomolous, Out-of-hospital Hospital (ref) 1 - GRADE: fair) 106,823 hospital delivered by VBAC births Out-of-hospital - 1.77 (1.12–2.79) 3,147 out-of-hospital Apgar 5 min <7 births Hospital (ref) - 1 Out-of-hospital - 1.62 (1.35–1.96) Ventilator support Hospital (ref) - 1 Out-of-hospital - 1.36 (0.75-2.46) NICU admission Hospital (ref) - 1 Out-of-hospital - 0.40 (0.29–0.57) Birth injury Hospital (ref) - 1 Out-of-hospital - 0.78 (0.58–1.04) 6-22

PREPUBLICATION COPY, UNCORRECTED PROOFS Wasden et al., 2017 Hospital database ≥36 weeks and one of the Out-of-hospital birth with HIE (ResQu: low) linked with New following: HIE York City vital  Apgar ≤5 at 10 min Planned home birth with Neonates w/o HIE - 1 records  resuscitation including HIE 69 cases of HIE endotracheal intubation or Neonates without HIE Out-of-hospital w/HIE - 44 (4.5–424.0) 276 matched controls bag/mask ventilation at 10 min  acidosis, defined as either Planned home w/HIE - 21 (1.7–256.4) umbilical cord arterial pH <7 or any postnatal arterial pH <7 within 60 min of birth  base deficit ≥16 mmol/L in an umbilical cord sample or any blood sample obtained within 60 min of birth (i.e., arterial or venous blood) NOTE: AABC = American Association of Birth Centers; CDC = Centers for Disease Control and Prevention; CNM = certified nurse midwife; GRADE = Grading of Recommendations, Assessment, Development, and Evaluation; HIE = hypoxic ischemic encephalopathy; NICU = neonatal intensive care unit; ResQu = Birth Place Research Quality. 6-23

PREPUBLICATION COPY, UNCORRECTED PROOFS MATERNAL OUTCOMES BY U.S. BIRTH SETTING Overuse and associated intervention-related maternal morbidity have been well documented in U.S. hospitals. Over the last several decades, cesarean birth rates have increased to 31.9 percent (Hamilton et al., 2019), which is higher than the generally recognized level at which lifesaving maternal and neonatal benefits outweigh the risks. Potential complications of cesarean births include a greater incidence of both maternal and infant outcomes including hemorrhage, infection, and admission to the intensive care unit; longer hospital stays; reduced breastfeeding success; and infant respiratory problems. A Healthy People 2020 goal is to reduce the nulliparous, vertex, term, singleton (NVTS) cesarean rate to 23.9 percent (Office of Disease Prevention and Health Promotion, 2019). As discussed in Chapter 2, hospitals across the United States vary widely in terms of rural or urban setting, level of care, resources available, and staffing models. Researchers have examined some of these differences and how they impact maternal outcomes, including interventions during birth and morbidities. Kozhimannil (2014) looked at differences between urban and rural hospitals, and found that rates of nonindicated cesarean birth and nonindicated labor induction were not dramatically different between the two in 2010 (16.9% and 17.8% for cesarean birth and 16.5% and 12% for induction, respectively). However, the rates of cesarean birth rose in both types of hospital between 2002 and 2010, and the rate of nonindicated labor induction rose disproportionately faster in rural compared with urban hospitals. Snyder and colleagues (2011) compared the rates of labor intervention in university and community hospitals across Ohio. They found that women giving birth in community hospitals were more likely to be induced at 37 weeks (1.7 adjusted odds ratio [aOR]), at 38 weeks (1.8 aOR), and at 39–42 weeks (2.0 aOR) compared with women in university hospitals. However, rates of cesarean birth did not differ between the two types of hospitals. Fingar and colleagues (2018) looked at rates of severe maternal morbidity across multiple kinds of hospitals. They found the outcome to be more prevalent in safety net hospitals, minority-serving hospitals, teaching hospitals, public (compared with privately owned) hospitals, and hospitals in the Northeast and South. Much of the research examining hospital-specific rates of intervention and morbidity consists of studies that compare hospital births with home or birth center births in order to draw conclusions about differences among settings. Because of their goal of making comparisons, these studies usually adjust the population studied to match the lower-risk profiles of women who give birth at home or in a birth center; for example, a study might look only at births that are singleton, vertex, and full-term. Thus, the rates gleaned from the hospital data cannot be used as representative of the rates for all hospital births, only of the rates for low-risk women in hospital settings. Recognizing this limitation of studies that compare home and birth center births with hospital births, these studies have consistently found higher rates of maternal intervention and morbidity in planned hospital births. We review this literature—systematic reviews, studies using birth registry data, and studies using vital statistics data—in detail below; the results are summarized in Table 6-5. 6-24

PREPUBLICATION COPY, UNCORRECTED PROOFS TABLE 6-5 Rate, Percentage, and Comparative Risk of Maternal Intervention-related Morbidity by Birth Setting Study Data Source/ Sample Inclusion/Exclusion Birth Setting Outcome Morbidity Morbidity Rate Adj. OR (95% Size Criteria % per 1,000 Live CI) Births Bovbjerg et al., 2017 MANA 2.0 dataset Planned home or birth Planned home and birth Cesarean delivery 5.4 (ResQu: high, (2004–2009) and 4.0 center births center births GRADE: low) dataset (2012–2014) Vaginal births only - - 47,394 out-of-hospital Any genital tract trauma 53.2 - - births Postpartum 3.4 - - hemorrhage >1000 cc Cheng et al., 2013 CDC birth certificate Singleton, term (37-42 Hospital birth Augmentation of labor (ResQu: moderate) data (2008) weeks), vertex, planned Planned home birth Hospital birth 22.2 - 1 12,039 planned home birth center and home births births Planned home birth 2.1 - 0.29 (0.27–0.31) 2,069,714 planned Induction of labor hospital births Hospital birth 25.7 - 1 Planned home birth 1.4 - 0.19 (0.18–0.22) Cheyney et al., MANA 2.0 dataset Planned home births not Planned home birth Cesarean birth 5.2 - - 2014a (2004–2009) transferred to another Episiotomy 1.4 - - (ResQu: high, 16,924planned out-of- provider prior to labor GRADE: Poor) hospital births 1st- or 2nd-degree perineal 40.9 - - laceration 3rd- or 4th-degree perineal 1.2 - - laceration If intrapartum transfer Oxytocin augmentation 22.0 - - Snowden et al., 2015 Oregon birth, infant Singleton, term (≥37 Hospital birth Augmentation of labor (ResQu: high, death, and fetal death weeks), cephalic, Planned home birth Hospital birth (ref) 26.4 - 1 GRADE: good) certificates (2012– nonanomalous Planned birth center birth 2013) Planned home birth 1.2 - - 75,923 hospital births Odds ratios were Planned birth center birth 1.1 - - 3,203 out-of-hospital calculated for planned Out-of-hospital birth - - 0.21 (0.19–0.24) births out-of-hospital Births with planned hospital Induction of labor delivery Hospital birth (ref) 30.4 - 1 6-25

PREPUBLICATION COPY, UNCORRECTED PROOFS 601 planned out of Planned home birth 1.3 - - hospital but birthed at Planned birth center birth 1.9 - - hospital Out-of-hospital birth - - 0.11 (0.09–0.12) Cesarean delivery Hospital birth (ref) 24.7 - 1 Planned home birth 0 - - Planned birth center birth 0 - - Out-of-hospital birth - - 0.18 (0.16–0.22) Severe perineal lacerations Hospital birth (ref) 1.3 - 1 Planned home birth 0.4 - - Planned birth center birth 1.4 - - Out-of-hospital birth - - 0.69 (0.49–0.98) Stapleton et al., 2013 AABC (2007-2010) Planned birth center Birth center birth Primary cesarean birth (ResQu: high, 15,574 birth center birth, singleton, vertex, Birth center birth 6.0 - - GRADE: poor) births live-born infant at ≥37 weeks gestation Thornton et al., 2017 AABC (2006–2011) Received prenatal care in Hospital birth Cesarean birth (ResQu: high, 8,776 planned birth birth center, singleton, Birth center birth Hospital birth 4.99 - 1 GRADE: poor) center births ≥37 weeks, admitted in 2,527 planned hospital spontaneous labor Birth center birth 4.14 - 0.62 (0.49–0.79) births Postpartum hemorrhage Hospital birth 4.63 - 1 Birth center birth 6.18 - 1.19 (0.97–1.48) NOTE: AABC = American Association of Birth Centers; CDC = Centers for Disease Control and Prevention; GRADE = Grading of Recommendations, Assessment, Development, and Evaluation; MANA = Midwives Alliance of North America; ResQu = Birth Place Research Quality. 6-26

PREPUBLICATION COPY, UNCORRECTED PROOFS Systematic Reviews Wax and colleagues (2010) published a systematic review of the literature on health outcomes following planned home and hospital births that provided data on morbidity in the home setting as well. The authors included all English-language, peer-reviewed publications from high-resource countries available at the time that reported maternal, fetal, and neonatal outcomes by birth setting. In alignment with the committee’s findings, these authors note that it is impossible to evaluate maternal mortality by birth setting, as these data are not reported in the literature, or small sample sizes do not allow for meaningful analysis. However, they were able to compare planned home and hospital births for a broad range of general morbidity and intervention-related morbidity indicators. They found that planned home births were associated with fewer maternal interventions, including epidural analgesia (9.0% vs. 22.9%; OR 0.24; CI 0.22–0.25); electronic fetal heart rate monitoring (13.8% vs. 62.6%; OR 0.10; CI 0.09–0.10); episiotomy (7.0% vs. 10.4%; OR 0.26; CI 0.24–0.28); operative delivery (3.5% vs. 10.2%; OR 0.26; CI 0.24–0.28); and cesarean birth in healthy, low-risk mothers (5.0% vs. 9.3%; OR 0.42; CI 0.39–0.45). Women who planned home births were also less likely to experience 3rd- and 4th-degree tears (1.2% vs. 2.6%; OR 0.35; CI 0.33–0.45), infection (0.7% vs. 2.6%; OR 0.27; CI 0.19–0.39), postpartum hemorrhage/bleeding (4.9% vs. 5.0%; OR 0.66; CI 0.61–0.71), vaginal lacerations (7.9% vs. 22.4%; OR 0.85; CI 0.78–0.93), and retained placenta (1.2% vs. 1.6%; OR 0.65; CI 0.51–0.83). This association between reduced morbidity and home birth settings may be attributable both to home birth models of care and to the fact that healthy women who are highly motivated to avoid interventions are proportionately overrepresented in home birth samples. Vital Statistics Studies More recent research on maternal outcomes by birth setting has largely upheld the findings of the Wax et al. (2010) systematic review. Using vital statistics data, Cheng and colleagues (2013 [ResQu: moderate]) found lower rates of interventions in the home compared with births in the hospital setting, including operative vaginal birth (0.1% vs. 6.2%; aOR 0.12; CI 0.08–017), labor induction (1.4% vs. 25.7%; aOR 0.19; CI 0.18–0.22), augmentation of labor (2.1% vs. 22.2%; aOR 0.29; CI 0.27–0.31), and use of antibiotics in labor (2.6% vs. 15.2%; aOR 0.40; CI 0.37–0.42). Three studies of birth center outcomes also used vital statistics data (MacDorman and Declercq, 201613; Li et al., 201714; Stephenson-Famy et al., 201815). 13 MacDorman and Declercq (2016 [ResQu: moderate, GRADE: poor]) examined trends in out-of-hospital births (N=59,674) that occurred between the years of 2004 and 2014. Data for this study came from the 47 states and Washington, DC using birth certificate data that had been revised after 2003. Results showed that out-of-hospital births increased by 72 percent over the 10 year period. Compared with women who had hospital births, out-of- hospital births had lower prepregnancy obesity and higher rates of breastfeeding initiation and vaginal birth after cesarean (VBAC). Results were significant at the p <0.05 level. 14 Li and colleagues (2017 [GRADE: poor]) conducted a population-based cohort study with matched birth certificate data (1996–2013) and Medicaid claims and hospital discharge abstracts in South Carolina to evaluate the validity of reports of neonatal seizures in infants born at home or in birth centers and then transferred to the hospital (N = 1,233). Their results showed birth certificates were not reliable as a sole source for analyzing the prevalence of neonatal seizures. 15 Stephenson-Famy and colleagues (2018 [ResQu: moderate, GRADE: poor) performed a retrospective cohort study using birth certificate data (2004 to 2011) of women who planned to give birth in a birth center (N = 6-27

PREPUBLICATION COPY, UNCORRECTED PROOFS Birth Registry Studies As noted above and in Chapter 5, studies using birth registries allow for analysis on an intention-to-treat basis; however, because reporting to registries is not mandatory these results may not be generalizable. In addition, these studies are descriptive and do not have an explicit comparison group. Cheyney and colleagues (2014a [ResQu: high, GRADE: poor]), using data from a national registry, describe outcomes of planned home births in the United States between 2004 and 2009. Among 16,924 women who went into labor intending to give birth at home, 89.1 percent completed their birth at home. The majority of intrapartum transfers from home to hospital were for slow, nonprogressive labors, and only 4.5 percent of the total sample required oxytocin augmentation and/or epidural analgesia. The rates of spontaneous vaginal birth, assisted vaginal birth, and cesarean birth were 93.6 percent, 1.2 percent, and 5.2 percent, respectively (Cheyney et al., 2014a). Four studies of birth center outcomes use data collected prospectively through the Perinatal Data Registry (PDR), a national, validated, online data collection tool developed by the American Association of Birth Centers (AABC) (Stapleton et al., 201316; Jolles et al, 201717; Thornton et al., 201718; Alliman et al., 201919). An additional study evaluates outcomes of the Strong Start Initiative—a project developed by the Center for Medicare and Medicaid Innovation (CMMI) and conducted between 2013 and 2017 (Hill et al., 2018; see Chapter 4). Birth center 7,118 planned birth center birth). A total of 93 percent of women gave birth at the birth center, and 7 percent gave birth in a hospital setting. Nulliparity was the most significant risk factor for hospital transfer (aOR 7.2; CI 5.3–9.8), followed by maternal age >40 (aOR 3.7; CI 2.1–6.7) and inadequate prenatal care (aOR 3.7; CI 2.7–5.2). 16 In a descriptive study, Stapleton and colleagues (2013 [ResQu: high, GRADE: poor]) evaluated outcomes of care for more than 15,500 women eligible for birth center admission in labor using the AABC’s data registry (called the Uniform Data Set, or UDS, at the time, now the PDR). The authors found a spontaneous vaginal birth rate of 93 percent and a cesarean birth rate of 6 percent; the remaining births were assisted vaginal births (Stapleton et al., 2013). The intrapartum transfer rate after admission to a birth center was 12.4 percent, and of those, 0.9 percent were considered emergency transfers. Intrapartum fetal deaths were 0.47 per 1,000, and neonatal deaths, excluding anomalies, were 0.40 per 1,000. 17 Jolles and colleagues (2017) analyzed data from Medicaid enrollees whose birth outcomes were recorded in the PDR. This study compared cesarean section rates between similar cohorts14 of healthy women who chose elective hospitalization versus a birth center birth. The authors found a significantly increased risk of cesarean section among planned hospital births. Cesarean rates for low-risk women admitted to a birth center were 2.7 percent, compared with 9 percent for low-risk women admitted to a hospital. 18 Using PDR data (Thornton et al., 2017 [ResQu: high, GRADE: poor]), exclusion criteria were used to form low-risk groups admitted to birth centers (n = 8776) and those that chose hospital admission (n = 2527). Comparing midwife-led birth center and hospital groups with midwifery care, the authors found a nonsignificant difference in cesarean birth rates (4.14% for birth centers vs. 4.99% for hospitals), a significant difference in breastfeeding initiation rates (94.5% for birth centers vs. 72.8% for hospitals), and no difference in the neonatal outcome composite (0.44% for both groups). 19 Alliman and colleagues (2019) found that Medicaid beneficiaries (N = 6424) enrolled in AABC Strong Start birth center sites experienced preterm birth rates of 4.4 percent and low-birthweight rates of 3.7 percent, compared with CDC birth certificate rates (N = 3,945,875) of 9.9 percent and 8.2 percent, respectively. The total cesarean rate was 12.3 percent, with a primary cesarean rate of 8.7 percent for births at Strong Start birth enters. Breastfeeding initiation was 92.9 percent compared with a national rate of 83.1 percent. In the birth center arm of Strong Start, eligible women participated in birth center prenatal care, and experienced these improved outcomes even if they elected hospital delivery. (See also Box 4-1). 6-28

PREPUBLICATION COPY, UNCORRECTED PROOFS studies using registry data consistently indicate that women who participate in birth center care experience low cesarean rates (6–12%) and high breastfeeding initiation rates (92–95%) (Stapleton et al., 2013; Jolles et al., 2017; Thornton et al., 2017). Summary Maternal outcomes by birth setting are remarkably consistent: low-risk home and birth center births are associated with lower rates of perineal laceration; reduced rates of medical intervention, including cesarean delivery; and higher rates of breastfeeding initiation and exclusive breastfeeding at 6–8 weeks postpartum. Most of the published data are from observational cohort studies, but several of those studies are based on large samples (Stapleton et al., 2013; Bailey, 2017; Hill et al., 2018) or include most or all birth center births in a region or country for a period of time (Birthplace in England Collaborative Group, 2011; Hollowell et al., 2017; Bailey, 2017; Grigg et al., 2017; Sprague et al., 2018). Lower rates of intervention and higher rates of breastfeeding are at least partially attributable to selection bias, wherein those who choose home or birth center birth are often highly motivated to achieve a physiologic birth and to breastfeed. The precise effect of selection bias on birth center outcomes is not known. However, the balance of evidence also suggests that there is something about the wellness-oriented, individualized, relationship-centered approach of midwifery care across home, birth center, and hospital settings that contributes to lower rates of medical interventions that can be dangerous when overused. To find reliable comparison groups for lower-risk birth center and home birth participants, some studies used exclusion criteria to compile low-risk groups so that women with no risk factors in each model could be compared. Other studies used regression analysis to control for differing risk levels to achieve more comparable groups for analysis. Overall, birth center outcomes are consistent for low- or lower-risk women for increased odds of spontaneous vaginal birth, decreased risk for cesarean and assisted vaginal birth, increased initiation and continuation of breastfeeding, and similar intrapartum and neonatal outcomes relative to hospital birth outcomes. Finding 6-3: In the United States, low-risk women choosing home or birth center birth compared with women choosing hospital birth have lower rates of intervention, including cesarean birth, operative vaginal delivery, induction of labor, augmentation of labor, and episiotomy, and lower rates of intervention-related maternal morbidity, such as infection, postpartum hemorrhage, and genital tract tearing. These findings are consistent across studies. The fact that women choosing home and birth center births tend to select these settings because of their desire for fewer interventions contributes to these lower rates. Intervention-related maternal morbidity also varies greatly across hospital settings. There are promising strategies and approaches to lowering the rates of non–medically indicated morbidity-related interventions in hospital settings (see Chapter 7 for further discussion of these models). 6-29

PREPUBLICATION COPY, UNCORRECTED PROOFS PATIENT EXPERIENCE AND SATISFACTION BY U.S. BIRTH SETTING Factors in Maternal Satisfaction and Relationship to Outcomes Maternal satisfaction across birth settings has typically been highest when women are supported in choosing the birth setting and provider type that align most closely with their value systems, individual pregnancy characteristics, and personal preferences. Multiple studies from Europe and Canada have measured maternal satisfaction (Janssen et al., 2006; Christiaens and Bracke, 2009; Lindgren and Erlandsson, 2010), but no study in the United States has systematically compared maternal satisfaction across birth settings. A systematic review with publications from multiple countries by Hodnett (2002) found the most critical predictors of satisfaction to be individual expectations, the amount of support received from caregivers, the quality of the caregiver–patient relationship, and maternal involvement in decision making. Several recent studies note high rates of maternal satisfaction when care is received from midwives regardless of location (Sandall et al., 2010; Macpherson et al., 2016), when doula care is provided (Hardin and Buckner, 2004; Kozhimannil et al., 2016; Thomas et al., 2017), by mode of delivery (Bossano et al., 2017; Alderdice et al., 2019), and when care is midwife-led at home and in birth centers (Fleming et al., 2016). For additional discussion of outcomes associated with doula care, see Box 6-1. BOX 6-1 Influence of Doulas on Outcomes across Settings Doulas care for women in every birth setting—home, birth center, and hospital. Some women utilize doula services throughout all phases of childbirth—ante-, intra-, and postpartum—while others use them during only one of the phases. A Cochrane review on continuous support during labor (which is one portion of what doulas provide) included 26 trials with nearly 16,000 participants. Bohren and colleagues (2017) found that continuous labor support may contribute to several positive outcomes in childbirth, including increased spontaneous vaginal birth; shorter duration of labor; decreased rates of cesarean birth, instrumental vaginal birth, use of any analgesia, and use of regional analgesia; and decreases in low 5-minute Apgar scores and negative feelings about childbirth experiences. No evidence of harms of continuous labor support were noted (Hodnett et al., 2013). A subgroup analysis found that effects of the doula model of labor support were greater than effects of continuous support provided by either a member of the hospital staff or someone from the woman’s social network (e.g., sister, friend) (Bohren et al., 2017). Observational studies published since that systematic review have confirmed the association between doula care and lower cesarean rates (Devereaux and Sullivan, 2013; de Sousa Soares et al., 2016; Kozhimannil et al., 2016). Additional studies have further replicated these findings, noting specifically that doula support that begins during pregnancy and continues through childbirth and the postpartum period is associated with higher rates of breastfeeding initiation and longer duration rates, as well as lower preterm birth rates. Two other positive outcomes noted in the literature are fewer low-birthweight babies and lower rates of postpartum depression (Trotter et al., 1992). As to why doula support may influence positive outcomes, one hypothesis is the doula’s instilling and boosting women’s confidence and self-efficacy. By being empowered to believe in 6-30

PREPUBLICATION COPY, UNCORRECTED PROOFS the power of their bodies and their innate ability to labor and give birth, women come to know that they are capable of far more than they may previously have thought. Particularly among disadvantaged populations, in whom self-efficacy can be particularly low, doula care has demonstrated great impact (Gruber et al., 2013). Many successful peer doula programs in the United States have been particularly efficacious in working with such populations. Such programs as the East Bay Community Birth Support Project in California, whereby previously incarcerated peers are trained as doulas, not only benefit the pregnant women but also decrease rates of recidivism among the women who become doulas (Stanley et al., 2015). Based on what is known about racial concordance between patients and their providers, peer doula programs that strive to achieve racial and community concordance would go far in advancing the agenda of improving maternal–fetal outcomes among women of color. An important study compared outcomes among Medicaid enrollees who did and did not receive doula care. Differences were noted in that the cesarean rate for the two groups were 22.3 percent and 31.5 percent, respectively. After controlling for various influential factors, odds of cesarean section were 40.9 percent lower for doula-supported births (Kozhimanni et al., 2013). A similar study among women of lower socioeconomic status with disproportionately higher poor baseline health, out of the State Department of Health in New York City, found that women paired with doulas had lower rates of preterm birth and low-birthweight babies. Additional studies report similar results (see, e.g., Kozhimannil et al., 2015; Thomas et al., 2017; Thurston et al., 2019). Potential cost savings to Medicaid programs that include funding for doula care could be substantial (Edwards et al., 2013; Kozhimanni et al., 2013). Doulas influence the bottom-line costs of birth through their positive effect on, among other outcomes, cesarean birth rates, time in labor, use of analgesia/anesthesia, and breastfeeding rates. Researchers looking at the economic impact of doula involvement in births in Wisconsin calculated (from 2010 birth data) an estimated savings of $28,997,754.80 if every low-risk birth (in hospitals) were attended by a professional doula. That figure breaks down to an estimated cost savings of $424.14 per delivery, or $530.89 per low-risk delivery (Chapple et al., 2013). [END BOX] In addition, it is known that one-to-one nursing care during labor and birth influences women’s satisfaction with their birth experience (Hodnett et al., 2002). Type of nursing care is a major factor in how women perceive the birth experience. Numerous studies informed by the voices of new mothers have found that women value support, encouragement, physical presence, explanations, and respect for their need for control (Corbett and Callister, 2000; Tumblin and Simkin, 2001; Hodnett, 2002; Matthews and Callister, 2004; Brown et al., 2009; Lyndon et al., 2017). Labor and delivery nurses have likewise been explicit about how the quality and quantity of their care is affected by inadequate nurse staffing (Simpson et al., 2012, 2016; Simpson and Lyndon, 2017a). In the context of inadequate staffing, nurses report that they are unable to accomplish all aspects of nursing care required because they are balancing the most pressing demands of the clinical needs of their additional patients. Labor support and physical presence at the bedside are the first aspects of care suspended when an obstetric unit is short-staffed (Simpson et al., 2012, 2016), even though multiple studies have shown that these aspects of care are essential to positive birth experiences. Box 6-2 elaborates on nurses’ influence on labor and birth outcomes. 6-31

PREPUBLICATION COPY, UNCORRECTED PROOFS BOX 6-2 Nurses’ Influence on Labor and Birth Outcomes Research on the influence on patient outcomes of nursing care during labor and birth is challenging, and thus there are limited data available to support these type of definitive links. It is difficult to connect individual aspects of nursing care to patient outcomes in part because of the way nursing care is documented in the electronic medical record and in part because nursing care is not billed as a specific inpatient service, but bundled into the fees charged for the hospital room and bed. Numerous assessment parameters for the mother and fetus are automatically generated from the electronic fetal monitor and transferred into the medical record without requirements for nurse verification. There has been a trend away from narrative nursing notes. Nurses can view data from the fetal monitor and enter data in the medical record remotely from a central station or in another patient’s room; thus nursing documentation does not equate to nursing bedside attendance, making that an unreliable factor in measuring the effect of nursing care. The value of nursing care is diminished by historical hospital billing practices not specifying care by registered nurses, which is inconsistent with the reality that patients are admitted to the hospital only if they need nursing care. Nearly all other aspects of the hospital stay, including but not limited to procedures and tests, can be done on an outpatient basis. Only if patients require around-the-clock nursing care are they deemed appropriate for hospital admission by third-party payers. Lacing billing codes embedded in the electronic medical record for other caregivers hinders the ability to measure nursing care. Much of the evidence on nurses’ influence on maternity outcomes is based on qualitative studies. However, several quantitative studies address nurses’ role in whether women have a cesarean or vaginal birth, including two randomized controlled trials (RCTs) (Hodnett et al., 2002; Gagnon et al., 1997). Two recent studies indicate that this issue requires more study (Edmonds et al., 2017; Greene et al., 2019). In 2002, a multicenter RCT compared one-to-one nursing care during labor with routine care among 6,915 women in the United States and Canada. Nursing care was provided to the intervention group by nurses who had been trained in labor support techniques. No clinical differences in outcomes were found between the groups (Hodnett et al., 2002). More than one- third of women in both groups had labor induction or augmentation with oxytocin, two-thirds in both groups had epidural anesthesia, and three-quarters in both groups had continuous electronic fetal monitoring. The researchers concluded that continuous labor support by nurses did not have an effect on clinical outcomes of women in perinatal units characterized by high rates of routine interventions (Hodnett et al., 2002). However, patient satisfaction was significantly higher among women who received one-to-one nursing care. Gagnon and colleagues (2007) retrospectively evaluated outcomes of 467 nulliparous women based on how many nurses had provided care during labor. They found an association between number of nurses for each woman during labor and risk of cesarean birth: the more nurses, the greater the risk. Gagnon and colleagues (2007) suggest a link between continuity of nursing care during labor and risk of cesarean birth. A recent focus on the rate of cesarean birth in the United States and its association with maternal morbidity and mortality has renewed interest in this topic. Two recent retrospective studies evaluated the role of the labor nurse in influencing mode of birth (Edmonds et al., 2017; Greene et al., 2019). Similar to Radin and colleagues (1993), these more recent studies limited 6-32

PREPUBLICATION COPY, UNCORRECTED PROOFS the patient population included in their analysis to women who were nulliparous, term, singleton, and vertex (NTSV). In both recent studies, a cesarean birth was attributed to a labor nurse and differences among nurses evaluated; however, different methods of attribution were used. Edmonds and colleagues (2017) attributed the cesarean to the labor nurse circulating for either a vaginal or cesarean birth. This method of attribution has limitations, as the nurse who attends the cesarean birth as the circulator cannot be assumed to have influenced the outcome or cared for the woman in labor; such factors as length of nursing care, quality of care, reason for the decision, decision maker, and patient assignment must be considered. This method of attribution also cannot be generalized, as many birthing hospitals change the nurse assignment for the circulating nurse when a decision for a cesarean is made. Radin and colleagues (1993) used the nurse present for birth as well, but further qualified attribution of the cesarean to the nurse having cared for the woman from at least 6 cm cervical dilation until birth; thus nursing care during labor was included as a potential influencing factor. Greene and colleagues (2019) attributed cesarean births to nurses using two methods: (1) the nurse who spent the most time with the patient during the first stage of labor, using documentation of maternal vital signs in the medical record as a proxy for nursing care; and (2) the nurse who initiated second-stage labor pushing. Based on these attribution criteria, these authors found differences in cesarean rates among groups of labor nurses. A limitation of their attribution method, however, is that most maternal vital signs are generated automatically by the electronic fetal monitor and simultaneously transferred to the medical record, and do not require bedside attendance by the labor nurse. Therefore, this method can potentially identify the nurse responsible for the woman in labor but cannot assess nursing care or the amount of time the nurse spent at the bedside. As others have found in studies attempting to attribute method of birth to individual physicians, attribution of the cesarean to an individual labor nurse is a complex issue, especially when retrospective data from the electronic health record are used as the data source, and much more study is needed before a generalizable method can be used in clinical practice. When asked, labor nurses are quick to say they influence outcomes, including women’s satisfaction with the birth experience and whether they have a vaginal or cesarean birth (James et al., 2003; Simpson et al., 2006; Sleutel et al., 2007; Edmonds and Jones, 2013; Lyndon et al., 2017; Simpson and Lyndon, 2017a). Nurses have reported routinely offering the following aspects of care to promote a vaginal and avoid a cesarean birth: offering emotional support; providing labor support (including ambulation, frequent repositioning, hydrotherapy, use of a peanut birthing ball, passive fetal descent in second-stage labor, appropriate titration of oxytocin for induction and augmentation of labor); sharing adequate and accurate information about what to expect; advocating on behalf of women; preparing and encouraging women to advocate for themselves; and communicating with physician colleagues on positive aspects of labor progress (Simpson and Lyndon, 2017b). These findings are consistent with those of earlier studies in which labor nurses reported advocating for more time to allow a chance for vaginal birth and using various emotional and physical labor support techniques to promote labor progress (James et al., 2003; Simpson et al., 2006; Sleutel et al., 2007; Edmonds and Jones, 2013; Lyndon et al., 2017; Simpson and Lyndon, 2017b). These aspects of nursing care in the context of labor management guidelines have been shown to be successful in decreasing cesarean births (Bell et al., 2017; Main et al., 2019; Tussey et al., 2015; White VanGompel et al., 2019). New mothers value the emotional and physical support of the nurse and feel that those aspects of nursing care are influential in determining birth outcomes (Lyndon et al., 2017). In one study, women 6-33

PREPUBLICATION COPY, UNCORRECTED PROOFS indicated that they assume their labor nurses will be skilled and competent to handle any childbirth emergency in a timely manner and are confident that maternal–fetal assessment is ongoing, so when they evaluated the quality of nursing care, emotional and physical labor support were the primary considerations (Lyndon et al., 2017). Physicians who attended births indicated that the nurse assigned to care for their patient in labor had a great deal of influence on the method of birth (Simpson et al., 2006; Lyndon et al., 2017). Physicians valued emotional and physical support during labor care as key influencing factors. It is likely that nursing care during labor and birth directly influences patient outcomes; however, measuring it has been challenging. Nurse researchers in the medical-surgical and intensive care unit specialties in the acute care setting have been studying the effect of nursing care on outcomes for many years. They have been able to link nurse staffing with risk of adverse patient outcomes in a variety of acute care settings (Kane et al., 2007; Lucero et al., 2010; Aiken et al., 2012; Ball et al., 2018; Griffiths et al., 2018; Recio-Saucedo et al., 2018). There are likely similar associations between nursing care during labor and birth and maternal–child outcomes; however, studies of these associations have yet to be conducted. In contrast to the study of patients in medical-surgical and intensive care units because of a medical or surgical problem requiring hospitalization, studying nursing care for a generally healthy population of women giving birth in a hospital and attempting to link that care with uncommon adverse outcomes has posed many methodologic challenges that have yet to be overcome. [END BOX] Some U.S. women report finding some aspects of their childbirth experience to have been negative or traumatic, including feeling inadequately supported during the perinatal period and having poor-quality relationships/interactions with their care provider. Lack of support—a poor outcome in itself—has been associated with other undesirable psychosocial sequelae, including increased rates of postpartum mood disorders (Bell and Andersson, 2016; Tani and Castagna, 2017), birth trauma (Simpson and Catling, 2016; Hollander et al., 2017; Reed et al., 2017), and cesarean regret (Porter et al., 2007; Burcher et al., 2016). A recent article by Vedam and colleagues (2019) reports findings from a convenience sample survey, administered by a multidisciplinary team that included service users, that was designed to capture the lived experiences of maternity care among diverse populations and across U.S. births settings. Patient-designed survey items included questions about verbal and physical abuse, failure to meet professional standards of care, autonomy, discrimination, poor rapport with providers, and substandard conditions within the health system. The researchers found that 17.3 percent of women, or one in six, had experienced at least one form of mistreatment during labor and birth (N = 2,138). Forms of mistreatment included loss of autonomy; being shouted at, scolded, or threatened; and having requests for help ignored or refused. Women who transferred to a hospital from a planned home or birth center birth or whose opinion on the best course of action differed from their provider’s reported even higher rates of mistreatment. Women’s experiences also differed significantly by birth setting, with 5.1 percent of women who gave birth at home reporting mistreatment versus 28.1 percent of women who gave birth in a hospital. A reduced likelihood of mistreatment was associated with giving birth vaginally, giving birth in a community setting (home or birth center birth), and giving birth with a midwife as the primary attendant regardless of location of care. Being White, multiparous, and older than 30 years of age were associated with lower levels of mistreatment. Mistreatment rates among women of color were consistently higher than those among White women, and this 6-34

PREPUBLICATION COPY, UNCORRECTED PROOFS relationship held even when the authors accounted for interactions between race and other characteristics, such as socioeconomic status. Any mistreatment was reported by 27.2 percent of low-income women of color versus 18.7 percent of low-income White women. Regardless of maternal race/ethnicity, having a Black partner was also associated with a higher rate of mistreatment. Experiences of care and perceived vulnerability to obstetric violence or obstetric racism appear to play important roles in shaping maternal decision making around where and with whom to give birth, as well as around what constitutes safety. (See also the discussion of institutional bias and discrimination in Chapter 4.) Summary Psychosocial outcomes, including several measures of dignity in the childbirth process, such as bodily autonomy, maternal agency, respectful care, and empowerment, are important. Some studies show that patient satisfaction is higher and reports of disrespectful care are lower among home and birth center births than among hospital births. Recent research has prompted greater understanding that various forms of disrespect and abuse can occur during the childbirth process in the United States and that rates and types of mistreatment vary by maternal race/ethnicity. Finding 6-4: Some women experience a gap between the care they expect and want and the care they receive. Women want safety, freedom of choice in birth setting and provider, choice among care practices, and respectful treatment. Individual expectations, the amount of support received from caregivers, the quality of the caregiver–patient relationship, and involvement in decision making appear to be the greatest influences on women’s satisfaction with the experience of childbirth. INTERNATIONAL STUDIES OF OUTCOMES BY BIRTH SETTING The committee examined studies of outcomes by birth setting internationally that could provide comparisons with the United States (see, e.g., Hutton et al., 2009, 2016; Janssen et al., 2009, 2015; Birthplace in England Collaborative Group, 2011; Schroeder et al., 2012; de Jonge et al., 2013, 2015, 2017; Homer et al., 2014; Vedam et al., 2014b; Zielinski et al., 2015; Bolten et al., 2016; Scarf et al., 2016, 2018). The committee chose Australia, Canada, the Netherlands, and the United Kingdom because they are high-resource countries and have relatively robust data on birth settings and outcomes from their vital statistics systems, as well as a range of well- conducted studies. Table 6-6 provides a comparison by country of types of providers, birth settings, and selected outcomes. Of course, it is important to note the deep differences among countries that shape the types of health care systems in each nation. The committee commissioned a study to identify these differences across the four identified countries (Kennedy et al., 2019). The paper authors note several important commonalities. First, the four countries share a commitment to integration of care across birth providers and systems. In these countries, out-of-hospital birth providers are part of an integrated, regulated maternity care system. For example, in Australia, the Netherlands and the United Kingdom, almost all vaginal births include at least one midwife in attendance, usually as the only professional present if the birth is without complications. In all four countries, 6-35

PREPUBLICATION COPY, UNCORRECTED PROOFS midwives are trained through a postsecondary education program and prepared to handle first- line complications. This integration translates to a second shared feature of maternity care systems in these countries: seamless transfer across settings. Strong systems are in place in all four countries to provide for collaboration, consultation, transfer, and transport when access to an obstetrician is needed. A third difference Kennedy and colleagues identified is the presence of universal access to primary and maternity care, including access to different (risk-appropriate) provider options during pregnancy and birth. This universal access to care (including preconception care) means women are neither without coverage prior to becoming pregnant nor dropped from health care coverage after they have had their baby, as is the experience of many Medicaid recipients in the United States (Ranji et al., 2019). In addition to these features, all four countries have adopted a practice of respectful care, including respect for maternal autonomy. This culture of respect informs the evidence-based guidelines in place in each country. These guidelines are intended to support clinical decision making for women and their providers and include information on appropriate risk selection and assessment, as well as out-of-hospital birth options. For example, the UK NICE Guidelines for Intrapartum Care (National Institute for Health and Care Excellence, 2017) clearly define the risk factors and situations in which consultation and (or) transfer of a laboring woman is required. Importantly, the guidelines support women’s choice in birth setting, reflecting the practice of trusting women to make appropriate decisions for themselves, their babies, and their families (Kennedy et al., 2019). Australia, Canada, the Netherlands, and the United Kingdom also provide additional social and welfare supports as compared with the United States, as well as increased availability of maternal and paternal maternity benefits. As a result, the level of disparities and inequity among childbearing people and risk propensities are different from those found among childbearing people in the United States. Accordingly, international comparisons are inherently limited, but do provide insights into how changes in the structure of health care systems might affect birth outcomes. TABLE 6-6 Comparison of Types of Providers, Birth Settings, and Selected Outcomes, by Country Year U.S. Australia Canada Netherlands UK a b c d Live births (per 1,000 births) 2017 3385.6 305.7 376.3 165.7 754.8c h Crude birth rate 2017 11.8e 12.4e 10.3e 9.9e 11.4e Children per woman (aged 15–49)c 2017 1.77 1.74 1.5 1.62 1.74 c Gross domestic product (GDP) per capita (US$) 2018 62,853 54,144 48,107 56,326 45,505 c Infant mortality (per 1,000 births) 2017 5.8 3.3 4.5 3.6 3.9 c Neonatal mortality (per 1,000 births) 2017 3.9 2.4 3.5 2.7 2.8 Perinatal mortality (per 1,000 births) (includes 2017 5.9 8.1 5.8 4.8 6.3 stillbirths)c Fetal death rate/stillbirth (per 1,000 births) 2017 - 7b 7.6f 7.7d 4.2g Maternal mortality (per 100,000 births) 2017 16.9 (2016)h 1.6c 6.6c 1.8c 6.5c % preterm births 2017 9.93a 8.7b 7.9f - 7i % low birthweight 2017 8.3c 6.7b 6.5c 6 (2016)c 6.9c 6-36

PREPUBLICATION COPY, UNCORRECTED PROOFS 2008– % severe maternal morbidityj 15.6 8.2 - - 5 2013 % cesarean births 2017 32a 34.6b 27.7c 16.2c 27.4c % births delivered by OB 2017 89.2a 74b - - - a b k % births delivered by MW 2017 9.9 26 10.8 - - % births delivered by FP/GP 2017 - - - - - % births in hospitals 2017 98.4 a 97 b 97.9f 71.5d - a b d % births in birth centers 2017 0.5 2 - 15.1 - a b f d % births at home 2017 0.1 0.3 2.1 12.7 2.1g % privately funded birth care 2017 49.1a - - - - a % publicly funded birth care 2017 43.0 - - - - 2013– GINI Indexc 41.5 (2016) 35.8 (2014) 34 (2013) 28.2 (2015) 33.2 (2015) 2017 NOTES: OB = obstetrician; MW = midwife; FP/GP = family physician/general practitioner. The GINI index measures the extent to which the distribution of income or consumption of expenditure among individuals/households within countries deviates from a perfectly equal distribution (Organisation for Economic Co-operation and Development, 2019). a Martin et al., 2018b. b Australian Institute of Health and Welfare, 2019. c Organisation for Economic Co-Operation and Development, 2019. d Perined, 2019. e The World Bank, 2019. f Statistics Canada, 2019. g Office for National Statistics, 2019. h Centers for Disease Control and Prevention, 2019a. i Chawanpaiboon et al., 2019. j Lipkind et al., 2019. k Canadian Association of Midwives, 2019. International Studies of Home Birth Outcomes When examining international studies of home birth outcomes, it is important to recognize that the context of the maternity care systems in the four countries the committee chose for comparison is very different from that of the current U.S. system, being characterized by universal health coverage and access, standardized high-level midwifery training, regulated risk-based selection of birth setting, and systems for transfer to a higher level of care when needed. Studies from the four comparison countries are often based on local or national registry data, allowing for an intention-to-treat approach to analysis. Although this minimizes selection bias, missing data are often treated as uninformative, an assumption that is likely incorrect (Wiegerinck et al., 2018). Overall, the international studies reviewed by the committee indicate that benefits result from fewer maternal interventions. They also generally find no difference in neonatal death between planned home and hospital birth cohorts. Notable exceptions exist, including infants born to primiparous women, for whom higher rates of perinatal mortality are seen in the United Kingdom (Birthplace in England Collaborative Group, 2011), and several studies from the Netherlands (Evers et al., 2010; Daysal, 2015; Wiegerinck et al., 2018) show 6-37

PREPUBLICATION COPY, UNCORRECTED PROOFS both higher perinatal mortality and an effect of distance on outcome. Table 6-7 shows international studies of neonatal outcomes by birth setting; Table 6-8 shows international studies of maternal outcomes by birth setting. 6-38

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The delivery of high quality and equitable care for both mothers and newborns is complex and requires efforts across many sectors. The United States spends more on childbirth than any other country in the world, yet outcomes are worse than other high-resource countries, and even worse for Black and Native American women. There are a variety of factors that influence childbirth, including social determinants such as income, educational levels, access to care, financing, transportation, structural racism and geographic variability in birth settings. It is important to reevaluate the United States' approach to maternal and newborn care through the lens of these factors across multiple disciplines.

Birth Settings in America: Outcomes, Quality, Access, and Choice reviews and evaluates maternal and newborn care in the United States, the epidemiology of social and clinical risks in pregnancy and childbirth, birth settings research, and access to and choice of birth settings.

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