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OCR for page 171
APPENDIX F Vital Statistics and Nonhospital Births:
A Mortality Study of Infants Born
Out of Hospitals in Oregon
Nancy Clarke in consultation with Anita B. Bennetts
Delivering infants in settings other than hospitals became increasingly
common in Oregon during the late 1970s. In 1974, only 1.5 percent of
all births took place in freestanding clinics, doctors• offices, homes,
and other nonhospital addresses, compared with 3.9 percent by 1979
(Oregon Center for Health Statistics, 1981, and unpublished data, 1981).
The number of births not attended by a physician also increased. In
1974, 1.2 percent of all Oregon births were attended by a lay midwife,
certified nurse midwife, chiropractor, naturopath, relative, friend, or
other person, compared with, 2.4 percent in 1979 (Oregon Center for
Health Statistics, 1981, and unpublished data, 1981). There has been a
siailar though less pronounced trend for the United States as a whole.
The proportion of births attended by midwives increased fro. 1.2 percent
to 1.6 percent between 1977 and 1979 (National Center for Health Statis-
tics, 1981). These changes in birth sites and delivery attendants have
stimulated an interest in the safety of nonhospital births.
It is extremely difficult to assess the relative safety of births
occurring in various settings with different providers. Definitive
assessments cannot be made until results have been obtained from pro-
spective studies that can control for maternal risks, demographic and
social characteristics, and intended delivery sites, and that can assess
outcoaes in terms of .orbidity for both mothers and infants. An impor-
tant preliminary step in designing these studies is to review existing
data on births and subsequent deaths for infants born elsewhere than in
a hospital. Mortality rates provide only crude indicators for measur-
ing birth outcomes, and retrospective studies using data collected for
entirely different purposes introduce many measurement problems. Con-
cluding that a causal relationship exists when mortality rates vary
between subgroups is inappropriate. Nevertheless, vital statistics
provide a relatively inexpensive means for generating hypotheses about
providers, sites, and populations for further study. Also, the ca.-
prehensive coverage of vital data plays a crucial role in emphasizing
the diversity of the providers and sites that must be included in the
description of nonhospital births. Finally, vital statistics can be
used to identify populations with excessive mortality, thereby serving
as an important tool for those interested in promoting public health.
171
OCR for page 172
U2
Shy et al. (1980) used vital statistics to exaaine differences in
infant mortality outcomes by site. They found that the infant mor-
tality rates for freestanding birth center deliveries were lower than
those for all Washington State residents and that home delivery mortal-
ity rates were higher than state resident figures. The authors cau-
tioned that biases are built into such comparisons because low-risk
pregnancies should have lower mortality rates. They reca.mended that
prospective studies should be based on the mothers' intention to have a
nonhospital delivery.
In this paper, vital records are used to examine the providers of
maternity care. The following pages describe the variation in neonatal
and infant .ortality for births occurring in all nonhospital settings by
the category of attendant indicated on birth certificates. There also
follows a discussion of the context for interpreting this variation.
NOHBOSPITAL BIRTHS IN OREGON
The nonhospital birth experiences vary by state. Regulations concern-
ing the births and who aay attend them are not the same, and the popu-
lations choosing a nonhospital setting may differ. A review of Ding-
ley's published data concerning Oregon's nonhospital births (Dingley,
1977, 1979) is relevant for an understanding of the mortality rates
presented in this paper.
Since 1977, approxiaately 4 percent of the live births in Oregon
have occurred in a setting other than a hospital. Oregon law prohibits
~ay persons from performing episiotomies and administering medications,
but no other limitations concerning birth attendants exist. Dingley's
descriptions of Oregon nonhospital births for 1976 and 1977 indicated
that the parents tended to be better educated than the parents selecting
hospital births. There were relatively fewer teenage .others, fewer
first births, and fewer immature and low birth weight babies than for
all births to Oregon residents. This suggested a de.ograpbic profile
that could favor the delivery of healthy infants.
When nonhospital births were categorized by the type of attendant,
however, sa.e indicators of low-risk pregnancies did not apply to all
categories. For births attended by fathers, mothers, other relatives,
friends, helpers, Followers of Christ, and other attendants, excluding
licensed professionals and midwives, a high percentage of .others had
achieved less than a twelfth-grade education and had received no pre-
natal care. Dingley expressed concern that approxtaately 15 percent of
all the mothers who delivered out of hospital had a history of previous
fetal deaths, a high-risk indicator. Her findings concerning .ortality
outcomes for 1976 were inconsistent with those of 1977.
These studies noted two subcultures with a large nuaber of nonbos-
pital deliveriess a caa.unity of Old Believers that had . .igrated from
Russia, and a religious ooaaunity called Followers of Christ. These
two groups constituted approxiaately one-fourth of the deliveries in
the •other and No Attendant• category.
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173
MBTIIOD
Tbe 1975-1979 birth and death recorda for all infants born out of hOs-
pital in Oregon were exDined. Those classified as •born en route•
were excluded because they were assu.ed to have been intended hospital
deliveries. Certainly other births were meant to have occurred in a
hospital but have been included in this analysis because they cannot be
identified. Tbe delivery attendants for all infants weighing 1,500
graas or less were contacted to assure that death reporting vas
ca.plete.
State and county staffs have done extensive field work in an atte.pt
to ensure as close to 100 percent coverage of nonhospital births as
possible. In this study, nonhospital births have been defined as all
deliveries that occurred in locations other than a hospital.
The birth attendants indicated on the certificates were classified
according to the following categoriesa
Other and
Licensed Attendant Midwife No Attendant
Medical doctors Certified nurse Relatives
Osteopaths midwives Friends
Naturopath& Lay aidwives who Helpers
Chiropractors identify thea- Followers of Christ
Registered nurses selves as such Old Believers
a.ergency -.dical Unknown attendants
personnel No attendant
These categories are certainly not ideal because there are significant
differences in training and orientation, for exa.ple, between a naturo-
path and a pbysician or between a lay aidwife and a certified nurse
•idwife (CMM). However, coding practices in 1975 and 1978 did not aake
finer distinctions.' The necessity of combining five years of data
in order to provide large enough nuabers for statistical reliability
prohibits the use of aore refined categories.
A birth was attributed to a lay aidwife if the attendant si.ply
identified herself as such or if her name appeared on a sufficient
nuaber of certificates for the birth certificate coders to recognize
her name and classify her as a lay aidwife. In recent years nearly all
lay midwives have been identified. However, as Dingley pointed out,
there are aany aidwives, particularly those in traditional and religious
camaunities, who do not sign certificates, preferring to have the
1 Data from 1976, 1977, and 1979 indicate that the aidwife category
consists of 57 percent lay midwives and 43 percent eRMa. The pro-
portion of births attended by lay midwives has been increasing. In
fact, 66 percent of the 1979 births in the aidwife category were
delivered by lay aidwivea. No differences in the death rates for
infants delivered by the two types of aidwives are apparent in the
three years for which aore detailed inforaation is available.
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174
TABLE 1 Selected Oregon and u.s. Honhospital Births and Subsequent
Death Rates (per thousand), 1970-1979
Nonhospital Nonhospital
Births Occurring Births Occurring All Births to
in Ore«Jon in Ore«Jon Oregon Residents All u.s. Births
Cate«Jory 1970-1974 1975-1979 1975-1979 1975-1979!.
Births 2,224 6,398 186,187 16,444,897
Neonatal deaths 58 48 1,475 165,696
Infant deaths 81 89 2,351 236,710
Neonatal 26.1 7.5 7.9 10.1
death rate
Infant death 36.4 13.9 12.6 14.4
rate
!Includes provisional estimates for 1979.
father or another relative sign as attendant (Dingley, 1977, 1979).
These cannot be identified and have been classified in the •other and
No Attendant• category.
This analysis consists of cross-tabulations of the rates, maternal
characteristics, and causes of death by attendant. caution is war-
ranted when interpreting these results because of the small sample
used, the low probability of neonatal and infant deaths, and the
inaccuracies in recording and lack of refinement in categorizing data
on type of attendant.
RESULTS
Infant and Neonatal Death Rates for All Nonhospital Births
Table 1 compares the figures for nonhospital births occurring in Oregon
during the past decade (1970-1974 and 1975-1979) to the 1975-1979 rates
for all Oregon residents and to the u.s. rates for the same period.
Although the number of nonhospital births has nearly tripled, the
number of neonatal deaths (deaths in the first 28 days) and infant
deaths (deaths in the first year) has stayed approximately the same.
As a result, the rates for both infant and neonatal deaths are con-
siderably less than half of what they were earlier in the decade. This
dramatic drop in the rates indicates that the year for which data was
collected aust be considered when evaluating and comparing research
findings.
For the last five years, there have been only small differences
between the death rates for nonhospital births and those for all
residents of Oregon (see Figure 1). The infant death rate for non-
hospital births is approximately one point higher (13.9 compared with
12.6). The neonatal death rate, which is a better indicator of problems
associated with pregnancy and delivery, is slightly lower (7.5 compared
with 7.9). Because of the small numbers involved, these differences
are not statistically significant (p <.OS). Both rates are lower
than the u.s. figures for all births.
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175
NEONATAL
~Licenaed
(I)
26 Ell CNMs end Lay Midwives
(I)
26
%
%
t- ~ Other end No Att•ndllnt t-
a: a:
CD
20 111111 All S~• R•idlntl iii 20
~ ~
a:
w
a..
16 -
a:
w
a..
16
(I) (I)
:J: :J:
t- 10 t- 10
<
w
<
w
c c
6 6
0 0
L- Out of Hospital ___. All L- Out of Hospital ___. All
Residents Residents
FIGURE 1 Neonatal and infant death rates for Oregon residents and for
nonhospital births by attendant, 1975-1979.
Infant and Neonatal Death Rates, by Attendant
Marked differences in the reported figures by attendant are apparent in
Table 2. Although the •other and Ro Attendant• category accounted for
only 28 percent of the nonhospital deliveries, this group contributed
to .ore than one-half of the neonatal deaths and nearly the same frac-
tion of the infant deaths. If the extreaely small infants are eliai-
nated and only the infants who weighed more than 2,500 grams at birth
are considered, the differences become even more pronounced.
The neonatal death rate of 13.9 for the •other and No Attendant•
deliveries is more than four times higher than the rate for lay
aidwives and certified nurse midwives and twice the rate for the
licensed aedical professionals. These differences are statistically
significant (p < .OS). Although the midwife rate is one-half the
licensed rate, this difference is not significant. Differences in the
infant death rates show a pattern similar to that of the neonatal
ratesJ the •other and Ro Attendant• infant death rate is nearly twice
the rate for the licensed attendants.
DISCUSSION
Extreme caution aust be exercised when interpreting these rates. With
vital records, a difference in mortality rates among settings may have
little to do with the safety of a planned delivery in a nonhospital
setting or with any particular attendant. The limitations associated
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176
TABLE 2 Nonhospital Births in Oregon and Subsequent Deaths by Type of
Attendant, Birth Weight, and Age at Death, 1975-1979
Licensed Other and Ro Total
Catec)ory Attendants Midwives!. Attendants Nonhoapital
Births 3,006 (471) 1,597 (25,) 1,795 (281) 6,398 (100,)
Neonatal deathsa 18 (371) 5 (10') 25 (52') 48 (100,)
Unknown weiCJht 0 0 2 2
2,500 9raaa 8 1 7 16
2,500 9raaa 10 (33') 5 (131) 16 (53') 30 (100,)
Infant death~a 38 (43,) 8 ( 91) 43 (48,) 89 (100')
Unknown weiCJht 0 0 2 2
2,500 9raas 12 1 7 20
2,500 9raaa 26 (391) 7 (10') 34 (511) 67 (100')
Neonatal death rate£a
All deaths 6.0 3.1 13.9 7.5
Infant death rate£a
All deaths 12.6 5.0 24.0 13.9
!Includes CHMa and self-identified lay midwives.
~ine infanta delivered by nonprofessional attendants had an unknown birthweiCJht.
The seven who died durinCJ the poatneonatal period have been added to the >2,500
catec)ory because all of th• lived 110re than one 110nth, none had any indication of
beinCJ pr...ture, and all died of causes not related to pr...turity, preC)nancy,
delivery, or perinatal conditions.
2.lter thousand.
with interpreting these rates are discussed in ter.a of ..asureaent
biases, risk factors, and causes of death--factors that may result in a
misplaced emphasis on the attendants rather than on the populations
served by those attendants.
Reporting Bias
The collection and coding of information from vital records introduces
a number of biases in studies concerned with evaluating outco.es
associated with nonhospital births. Pirat, mortality ia only a crude
indicator of unsatisfactory pregnancy outca.ea, and large populations
are required to produce statistically significant ratea. Pive years of
birth and death data for Oregon do not provide a sufficient population
for adequately detailed comparisons. Second, the categories of attend-
ants may be misleading. Por example, although the neonatal death rate
for all licensed attendants combined is 6.0 per 1,000 births, the rate
for naturopath& and physicians may be vastly different. Furthermore,
because the tera lay midwife bas no official definition in Oregon tbia
category undoubtedly includes people with quite different akilla and
practices. A third factor to be considered ia the possibility of
incomplete registration. Although there are no means for aaaeaaing
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177
underreporting of deaths, the severity of the consequences for failure
to report a death suggests that this is probably a rare event. However,
nonhospital births are known to be underreported because these births
are soaeti..s registered after the children.are more than one year
old. This difference could result in exaggerated mortality rates for
one group when compared with another.
A last set of i~rtant considerations concerns the differences
between the reported and the intended site and provider. A midwife
with appropriate physician and/or hospital backup may consult a phy-
sician as well as transfer a patient to a hospital in the event that
complications arise during labor and delivery. · But the birth record
contains only information on the final site and provider. Therefore,
the vital records identify many complicated deliveries as hospital-
based or physician-attended when the birth was actually planned to be
nonhospital with a aidwife attendant. A bias in the opposite direction
also exists because some of the nonhospital births may be deliveries
for mothers who were unable to obtain medical assistance quickly when
labor began. The possibility also exists that a father or other rela-
tive is asked to sign as attendant when a delivery by any attendant
goes awry.
Bias Due to Variation in Risk Status
The reporting biases in the mortality rates presented in this paper are
•inor compared to the biases introduced in these rates by variations
a.ong the populations. The medical, social, and demographic risks pre-
sented to the different categories of attendants undoubtedly account
for much of the variation in the rates. Birth certificates contain only
limited information about maternal risks, and data are only available
for 1976, 1977, and 1979. Nevertheless, the differences in the charac-
teristics of mothers in the three attendant categories emphasize the
necessity of considering these variables. Data concerning parental
educational attainment and mothers' prenatal care show a pronounced
disadvantage for mothers in the •ather and No Attendant• category.
An examination of prenatal-care history makes it apparent that the
births in the third attendant category do not represent the ideal of
well-screened mothers anticipating normal deliveries (Figure 2). In
the three years for which information is available, more than one-fourth
(28 percent) of the mothers without a licensed attendant or a midwife
bad received no prenatal care. For the same period, the figure is less
than 1 percent for the mothers in the licensed attendant and midwife
categories.
The mother's lack of education is another characteristic shown to
be associated with higher infant and neonatal mortality. Of those who
answered the education question on the certificates during the three-
year period, slightly more than one-third of all mothers who delivered
out of hospital reported exactly 12 years of education. However, 29
percent of the mothers who delivered without a licensed attendant or a
•idvife had less than a high-school education, coapared with 13 percent
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178
30
~Licensed
25 111111 CNMs and Lay Midwives
en ~ Other and No Att8ndant
I=
~
20
ID
IL.
0 15
1-
z
w
u
~
w 10
1:1..
5
+
+
L- No Prenatal Care ....J Mother< 12 Years Education
PIGURE 2 Percent of births in aaternal risk category for births
occurring out of hospital, by type of attendant, 1976, 1977, 1972.
of those with a licensed attendant and 9 percent of those with a aid-
wife. Although more than one-half (53 percent) of the mothers attended
by licensed professionals and midwives had some college education, only
36 percent of the •other and No Attendant• category reported this level
of education. Pathers showed patterns of educational attainment that
were similar to those of the mothers.
Other data concerning varying numbers of high-risk .others bY the
type of attendant are ambiguous. Although mothers with a reported
complication of pregnancy accounted for 2 percent of each nonhospital
attendant category (compared with 5 percent for all state resident
births), it is doubtful that such problema as anemia and Rh incompati-
bility, which are common for medically attended births, would be diag-
nosed for the large number of mothers with no prenatal care and without
a licensed attendant or a midwife. The risk factors concerning mater-
nal age and pregnancy history did not vary by type of attendant.
The large differences in the educational attainment and prenatal
care of the populations served by the three attendant categories used
in this analysis are an indication that other medical, social, and
demographic characteristics must vary as well.
Causes of Death
The above discussion of maternal risks demonstrates a need to consider
not only the providers of care but also the populations served. An
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179
T~ 3 Ronhoapital Births in Oregon and Subsequent Deaths of Infanta
with Birth Weights Higher than 2,500 Graaa, by Type of Attendant, Age,
and Cause of Death, 1975-1979
Licensed Other and Ho Total
catec:Jory Attendanta Midwives!. Attendants Honhospital
Births 3,006 1,597 1,795 6,398
Deaths by cause
Pregnancy, delivery
and per ina tal
conditions
Neonatal 6 1 8 15
Infant 7 1 8 16
Congenital anoaalies
Neonatal 3 1 2 6
Infant 7 1 5 13
other causesa.2
Neonatal 1 2 6 9
Infant 12 5 21 38
Sudden Infant
Death Syndraae g£ ~ 1~ 22
External causes
(IIOtor vehicle,
drowning, acci-
dent, assault,
undetermined) 1 s!t 6
PneUIIOI\ia and
upper respira-
tory tract
infection 3 3
Meningitis 1 1 2
Malignant
neoplasas 2 2
Septicemia 1 1
Skin infection 1£. 1
Intestinal
obstruction 1 1
Infant death rate
(per thousand) for
other causes 4.0 3.1 11.7 5.9
Aincludes CMMs and lay midwives.
2rroa categories 000-739 and 780-999 in World Health Organization, 1977.
£Includes one neonatal death.
~Includes two neonatal deaths.
~Includes three neonatal deaths.
examination of the causes of death for infanta born out of hospital
provides further evidence that addressing the attendants rather than
the population served can be misleading. Table 3 and Figure 3 present
the causes of death for infants who were born out of hospital and who
weighed at least 2,501 graaa at birth.
OCR for page 180
180
35
~ Pregnancy Delivery end
Perinatal Conditions
30
1111111111 Congenital Anomalies
25
llllllmllll Other eeu-
(SIDS, external ceu... pneumonia,
(I) meningitis, malignant neaplans,
:I:
1- skin infection, intestinal obltructionl
<(
w 20
c
IL.
0
a: 15
w
a:l
~
~
z 10
5
0
,,
..
c:
•
c: c:
... ::
II II
e<(
.J:. 0
c5z
PIGURE 3 Infant deaths for births occurring out of hospital, by cause
and type of attendant, 1975-1979.
More than one-half of all the deaths of infanta born out of hos-
pital were attributed to causes not directly related to pregnancy,
delivery, perinatal conditions, or congenital anoaaliea. These other
causes account for a large proportion of the differences in mortality
rates between attendant categories. Nearly one-half of the neonatal
deaths and almost two-thirds of all infant deaths in the •Other and No
Attendant• category were attributed to causes such as Sudden Infant
Death Syndrome (SIDS), external causes, and other diseases. This COB-
pares with one-sixth of the neonates and approximately one-half of the
infanta in the licensed attendant category. This is important because
the number of infant deaths atributed to other causes was more than
twice the number attributed to pregnancy, delivery, and perinatal con-
ditions. The 21 infant deaths due to other causes in the •other and No
Attendant• category translates to a cause-specific rate of 11.7 per
1,000 births, which is significantly different fro. the 4.0 per 1,000
births rate for licensed attendants (p <.OS). Differences in the
rates due to perinatal conditions and congenital ana.aliea are not
significant.
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181
The list of other causes emphasizes the need to consider the entire
social and health care environment of the population served by the
•Other and No Attendant• providers. In nearly one-half (10) of the
cases of other causes for other attendants, the state medical examiner
could find no sign of disease and attributed death to SIDS. Another
one-fourth (5) of the cases were due to external causes such as
automobile accidents, drowning, and homicides. Three infants (not
neonates) died of pneumonia and upper respiratory tract infections.
Meningitis, septicemia, and skin infection each resulted in one death.
CONCLUSIONS
State vital statistics can be used as a basis for public health efforts
to improve the outcome of nonhoapital births. Such statistics can
identify problem areas and suggest hypotheses for further study. Im-
pedimenta to using the data include incomplete and missing informa-
tion on such ite. . as delivery site and personnel, reporting bias, and
variation )n risk factors associated with the population.
The data for Oregon indicate that more than one-half of the infant
deaths associated with nonhospital births occurred in a population that
delivered without the aid of a licensed attendant or a midwife. This
s ... group had a poor prenatal-care history, a large proportion of par-
ents with leas than a twelfth-grade education, and, probably, a poor
medical and demographic risk profile as well. In Oregon, attempts to
influence the outcomes of nonhospital births will require much more
investigation of those deliveries attended by relatives, friends,
helpers, Followers of Christ, Old Believers, unknown attendants, and
those with no attendant at all.
RBFBRBNCBS
Dingley, B. 1977. Birthplace alternatives. Oregon Health Bulletin
55(10):1-4.
Dingley, B. 1979. Birthplace and attendants, Oregon's alternative
experience, 1977. Women and Health 4:239-253.
National Center for Health Statistics. 1981. Advance report of final
natality statistics, 1979. Monthly Vital Statistics Report 30(6,
Supplement 2).
Oregon Center for Health Statistics. 1981. Oregon Vital Statistics.
Portland: State Department of Ruman Resourc~s.
Shy K. K., F. Frost, and J. Ullom. 1980. Out-of-hospital delivery in
Washington State 1975-1977. American Journal of Obstetrics and
Gynecology 137:547-552.
World Health Organization. 1977. International Classification of
Diseases, Ninth Revision. Geneva: World Health Organization.
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