4
Patterns of Contraceptive Use

Chapters 2 and 3 summarized the demography of unintended pregnancy and its consequences. The composite picture that emerges is that unintended pregnancy is common in the United States and that much would be gained if a higher proportion of pregnancies were intended at conception. This surely is not a new thought, nor is it particularly controversial.

The complexities begin to mount, however, when the next issue is approached—namely, understanding why there are such high rates of unintended pregnancy in the United States. What is it about our culture, our education and values, our methods of contraception, or our health care system that produces the patterns described in Chapter 2. This is more than a rhetorical question. It is, in fact, the essence of the challenge for policy leaders and others who are searching for ways to decrease the proportion of pregnancies that are unintended.

The direct cause of unintended pregnancy, of course, is sexual activity accompanied by contraceptive misuse, failure, or nonuse altogether. Accordingly, this chapter explores patterns of contraceptive use as they bear on unintended pregnancy. Trends in the use of different contraceptive methods are discussed, including both sterilization and reversible contraception. A discussion of contraceptive use among men is also included, covering use at first intercourse as well as at different stages of the reproductive life span; this discussion is followed by commentary on so-called dual-method contraception—that is, the use of two methods of contraception simultaneously. The chapter also includes with a brief discussion of the intersection of unintended pregnancy with sexually transmitted diseases (STDs). The next three chapters, Chapters 57, consider the many factors that influence contraceptive use and therefore the occurrence of unintended pregnancy.



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--> 4 Patterns of Contraceptive Use Chapters 2 and 3 summarized the demography of unintended pregnancy and its consequences. The composite picture that emerges is that unintended pregnancy is common in the United States and that much would be gained if a higher proportion of pregnancies were intended at conception. This surely is not a new thought, nor is it particularly controversial. The complexities begin to mount, however, when the next issue is approached—namely, understanding why there are such high rates of unintended pregnancy in the United States. What is it about our culture, our education and values, our methods of contraception, or our health care system that produces the patterns described in Chapter 2. This is more than a rhetorical question. It is, in fact, the essence of the challenge for policy leaders and others who are searching for ways to decrease the proportion of pregnancies that are unintended. The direct cause of unintended pregnancy, of course, is sexual activity accompanied by contraceptive misuse, failure, or nonuse altogether. Accordingly, this chapter explores patterns of contraceptive use as they bear on unintended pregnancy. Trends in the use of different contraceptive methods are discussed, including both sterilization and reversible contraception. A discussion of contraceptive use among men is also included, covering use at first intercourse as well as at different stages of the reproductive life span; this discussion is followed by commentary on so-called dual-method contraception—that is, the use of two methods of contraception simultaneously. The chapter also includes with a brief discussion of the intersection of unintended pregnancy with sexually transmitted diseases (STDs). The next three chapters, Chapters 5–7, consider the many factors that influence contraceptive use and therefore the occurrence of unintended pregnancy.

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--> Patterns of Contraceptive Use and Unintended Pregnancy In 1988, there were more than 3 million unintended pregnancies in the United States. Slightly fewer than half of these unintended pregnancies occurred among women who reported using reversible contraception, and slightly more than half among women who reported not using contraception despite no apparent intent to become pregnant (Harlap et al., 1991). In absolute numbers, this means that, in 1988, approximately 21 million women who reported using reversible methods of contraception experienced 1.5 million unintended pregnancies. And approximately 4 million women who reported that they were not actively seeking pregnancy and not using contraception at the time that they became pregnant experienced an additional 1.7 million unintended pregnancies (Mosher, 1990). Figure 4-1 was developed to help provide a better understanding of this complicated connection between contraceptive use and unintended pregnancy. Using data from the National Survey of Family Growth (NSFG), this figure shows that in 19881 there were approximately 58 million women of reproductive ages 15–442 in the United States (Tier 1). Six out of 10 of these women reported using contraception; 4 out of 10 reported that they were not currently using contraception (Tier 2). The women who reported using contraception are divided into two groups: those who relied on contraceptive sterilization, either their own or their partner's (Group A), and those who used reversible contraception (Group B). Of these two groups, only the women in Group B have an appreciable risk of becoming pregnant unintentionally, inasmuch as sterilization is so effective. Similarly, women who reported that they were not currently using contraception are divided into two groups. The first—Group C—is comprised of women who were currently sexually active (i.e., they reported having had 1   As this volume was being completed, data on contraceptive use from the 1990 National Survey of Family Growth (NSFG) telephone reinterview survey were published (Peterson, 1995). These data are used sparingly through this chapter because of concerns about the response rates among some subpopulations. 2   This number is slightly different from the comparable number in Table 2-1 which is for 1990, not 1988, and includes 13- and 14-year-old girls. Data from 1988 (which exclude 13- and 14-year-olds) are used here because this chapter relates contraception to unintended pregnancy, and 1988 data on unintended pregnancy are more complete than 1990 data.

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--> Figure 4-1 Contraceptive status of women experiencing unintended pregnancies, 1988. As noted in Chapter 2, the best available estimate of the pregnancies that are unintended is 57 percent. This estimate is based on the 1988 NSFG and supplemented by abortion data from 1987 compiled by The Alan Guttmacher Institute and the Centers for Disease Control. Sources: Harlap S, Kost K, Forrest JD. Preventing Pregnancy, Protecting Health: A New Look at Birth Control Choices in the United States. New York, NY: The Alan Guttmacher Institute; 1991; Mosher WD. Contraceptive practice in the US, 1982–1988. Fam Plann Perspect. 1990;22:198–205.

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--> intercourse in the 3 months before the survey interview),3 were fertile (neither they nor their partner had been contraceptively sterilized and they did not believe they were infertile for other reasons), and were not pregnant, postpartum, or trying to conceive. That is, they were clearly at risk of experiencing an unintended pregnancy because they used no contraception, but at the same time, they report that they were not actively planning for, or desiring, a pregnancy at that time. The other group, Group D, includes women who were not using contraception, but who were highly unlikely to experience an unintended pregnancy. These women were sterile for noncontraceptive reasons, sterile for reasons other than surgery, already pregnant or in the immediate postpartum period, trying to conceive, had never had intercourse, or were not currently sexually active (Mosher, 1990). Thus, unintended pregnancy derives almost entirely from two groups. It occurs among women using reversible contraception (Group B), because contraceptive methods may fail or be used improperly, as discussed later in this chapter. It also occurs frequently among the relatively small group of women using no contraception who nonetheless are not actively seeking pregnancy (Group C), simply because sexual intercourse without the protection of contraception often leads to pregnancy. Table 4-1 shows how women who do not intend to become pregnant are distributed between Groups B and C, according to several demographic variables. The table shows, for example, that among all sexually active women ages 40–44 who do not intend to become pregnant and who are not contraceptively sterilized, almost one-fourth (23.8 percent) use no contraceptive method, a finding that helps to explain the high rates of unintended pregnancy observed among older women. It is important to stress, however, that women typically move back and forth between these two groups, making the distinction between them one that only applies at a given point in time. In particular, the category of contraceptive nonuse (Group C) includes a wide variety of women. It clearly includes women who consistently use no contraception over months or even years, many of whom have experimented with nonuse, have not become pregnant, and have gradually come to believe that they are subfecund—and in fact sometimes are. But it also includes women exhibiting only occasional periods of nonuse. Indeed, the majority of women in this nonuse category have used contraception at some previous time (Forrest, 1994b). For example, a woman may use a reversible method for a year and then, for a variety of reasons, stop using it for several moths, perhaps intending to try a different method shortly. This is illustrated 3   This definition of sexual activity is slightly more constrained than the definition in Chapter 2, in that it includes only those women who are currently sexually active, not those who have ever had sexual intercourse.

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--> TABLE 4-1 Sexually Active Women Who Reported No Intent to Become Pregnant, and Were Either Using Reversible Contraception (Group B), or Not Using Contraception (Group C), by Age, Marital Status, and Poverty Level, 1988a   Percentage of Women     Characteristics Reversible Contraception (Group B) No Contraception (Group C) Total Total 84.7 15.3 100.0         Age       15–19 78.5 21.5 100.0 20–24 87.0 13.0 100.0 25–29 86.8 13.2 100.0 30–34 87.2 12.8 100.0 35–39 84.3 15.7 100.0 40–44 76.2 23.8 100.0 Marital Status       Never married 80.2 19.8 100.0 Married 89.4 10.6 100.0 Formerly married 84.5 15.5 100.0 Poverty level       <100% 71.1 28.9 100.0 100–199% 82.1 17.9 100.0 >200% 88.2 11.8 100.0   a   The denominator for these percentages is women who reported that they did not intend to become pregnant minus women who reported that they used contraceptive sterilization (i.e., all of the women in Groups B and C, but not those in Group A). SOURCE: Forrest JD. Contraceptive use in the United States: Past, present and future. Adv Popul. 1994a;2:29–48.

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--> by the finding that 28 percent of contraceptive-using married women discontinue their contraceptive method during any given year without the intention of becoming pregnant. Approximately 50 percent of these women immediately switch to another method of birth control, and the other half go through a period of contraceptive nonuse (Grady et al., 1988; Henshaw and Silverman, 1988). Of course, even temporary nonuse may result in an unintended pregnancy, especially if the nonuse interval is extensive. From a practical point of view, however, it is important to recognize that unintended pregnancy results both from spells of contraceptive nonuse and from contraceptive failure or misuse, and that the strategies needed to reduce the incidence of unintended pregnancy in each of these two groups may well be different. For example, encouraging women who are currently using contraception (Group B) to be even more careful with their methods of contraception or to use more effective methods (e.g., to switch from foam to oral contraceptives) will be quite a different task from helping a woman to confront the risks of being sexually active, not desiring pregnancy, and using no contraception at all (Group C). Unintended Pregnancy Among Women Using No Contraception (Group C) As shown in Figure 4-1, only 6.7 percent of women of reproductive age can be described as not intending pregnancy, yet not using contraception. This small group (Group C) contributed a full 53 percent of all unintended pregnancies in 1988, demonstrating how risky it is to engae in sexual intercourse without contraception when pregnancy is not being actively sought. Table 4-2 highlights the demographic attributes of the women in Group C. It reveals, among other things, that contraceptive nonuse is seen among women of all ages. Nonuse among teenagers merits an additional comment. Some portion of this phenomenon reflects the common experience of having used no contraception at first intercourse, which is related to the age at first intercourse. The age of first intercourse has declined in recent years: higher proportions of adolescent men and women reported being sexually experienced at each age between the ages of 15 and 20 in 1988 than in the early 1970s. The percentage of women who had had intercourse before their 18th birthday rose from 35 to 56 percent during this time period; for men the percentage increased from 55 to 73 (The Alan Guttmacher Institute, 1994; see also Laumann et al., 1994). This is significant for unintended pregnancy because the younger the age of first intercourse, the less likely that contraception will be used at that first intercourse or in the months directly following the event. Again, though, as shown in Table 4-2, the majority of nonusers are not adolescents.

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--> TABLE 4-2 Sexually Active Women Who Reported No Intent to Become Pregnant and Were Not Using Contraception (Group C), by Age, Marital Status, Poverty Level, and Race and Ethnicity, 1988a Characteristics Percentage Age   15–19 20.6 20–24 20.1 25–29 21.1 30–34 15.2 35–39 11.5 40–44 11.5 Total 100.0 Marital Status   Never married 52.1 Married 33.7 Formerly Married 14.2 Total 100.0 Poverty Level   <150% 38.2 150–299% 23.5 >300% 38.3 Total 100.0 Race/ethnicity   White 61.1 Black 19.7 Hispanic 13.8 Other 5.4 Total 100.0     a   The denominator for these percentages is sexually active women who reported not intending to become pregnant and not using contraception. SOURCE: National Center for Health Statistics. Unpublished tables from the 1988 National Survey of Family Growth. Tables 1-1, 1-2, 1-4, and 1-6 for 1988.

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--> Unintended Pregnancy Among Women Using Contraception (Groups A and B) Women who report using contraception—a much larger group than those who do not—also experience unintended pregnancy and, as noted in Figure 4-1, contribute nearly half of all unintended pregnancies. Unintended pregnancies occur almost exclusively among women reporting use of reversible contraception (Group B). Women who have been sterilized for purposes of contraception or who are relying for protection against pregnancy on their partner's sterilization (Group A) contribute virtually not at all to the pool of unintended pregnancy. Nonetheless, it is important to note several aspects of this group because so many women and couples rely on sterilization to prevent pregnancy, particularly in the later phases of the reproductive life span. Contraceptive Sterilization Nearly 40 percent of all women who report using contraception relied on contraceptive sterilization (either their own or their partner's) to avoid unintended pregnancy in 1988. Female sterilization is used much more frequently than male sterilization. Although male and female sterilization rates were nearly equivalent in the 1970s, by 1988, 28 percent of women using contraception relied on female sterilization and only 12 percent relied on their partner's use of vasectomy (Mosher and Pratt, 1990). The 1990 NSFG telephone reinterview survey and the 1992 and 1994 Ortho Birth Control Studies indicate that heavy reliance on sterilization has continued into the early 1990s, and female sterilization has continued as the predominate form (Forrest and Fordyce, 1993; Ortho Pharmaceutical Company, 1994; Peterson, 1995).4 Several factors probably account for the growing preference for female rather than male sterilization, despite the fact that the male sterilization procedure is safer and less expensive. The growing availability of quick and safe procedures such as laparoscopy during the 1970s and 1980s made it easier for women to choose sterilization, and the legacy of medical reticence, exemplified 4   Because data from the 1988 and 1990 NSFG predate the introduction of both injectable and implantable hormonal contraceptives, they are supplemented in this chapter by data from the 1992 and 1994 Ortho Birth Control Studies. The Ortho Birth Control Studies are an annual survey by the Ortho Pharmaceutical Corporation of contraceptive attitudes and the contraceptive methods used. The value of this survey is somewhat limited, however. Random sampling is not used, and the surveys tend to underrepresent black women and households with annual incomes greater than $50,000. Nevertheless, they do provide some insight into contraceptive use in the 1990s.

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--> by the ''120 rule,"5 eased as well. The sterilization decision has come to be based more on client request and preference rather than provider opinion, and female sterilization has increasingly come to be seen as the most foolproof method of contraception by women who become tired or distrustful of other methods and who appreciate the control that sterilization provides. Women also may choose sterilization because the burden of contraception most often falls on them. In addition, obstetricians and gynecologists may be more likely to discuss female sterilization with women than internists (or other clinicians) are to discuss male sterilization with men. Reversible Contraception Women currently using reversible contraception—approximately 21 million in 1988—contribute slightly less than half of all unintended pregnancies (Group B). Their demographic attributes are shown in Table 4-3. The dynamics of pregnancy occurring despite the use of contraception are unclear, and both method failure (i.e., the condom broke because of manufacturing problems) and user failure (i.e., the condom broke because it was used incorrectly) must be taken into account. It is often difficult, as a practical matter, to distinguish clearly between a genuine contraceptive failure and the failure of an individual or couple to use a method properly and consistently. Only with methods that require no specific action once they are established, such as a contraceptive implant, can these distinctions be made with certainty. One of the most important and difficult problems faced in understanding how pregnancy can occur in the presence of contraception is that the primary data source for computed rates is interviews (and questionnaires) with women and men in which the respondents are asked about their patterns of contraceptive use at the time that an unintended pregnancy occurred. Most people being interviewed understand intuitively that to admit that no contraception at all was being used or that it was being used improperly, despite no desire to become pregnant at the time, is in some sense an embarrassing admission, however honest it might be. The socially desirable answer, of course, is to say that contraception was being used carefully and consistently, but that an unintended pregnancy occurred anyway. Because of this problem, estimates of genuine contraceptive failure (the method was used perfectly, but pregnancy occurred nonetheless) are probably inflated by some unknown, but real factor. This is not 5   Clinicians used to refuse to sterilize women until the patient's age multiplied by the number of live births she had had equaled 120; for example, a physician might refuse to sterilize a 30-year-old woman who had had three live births (30 × 3 = 90), but might agree to do so if she had had four live births (30 × 4 = 120)—hence the "120 rule."

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--> TABLE 4-3 Women Who Reported No Intent to Become Pregnant and Were Using Reversible Methods of Contraception (Group B), by Age, Marital Status, Poverty Level, and Race and Ethnicity, 1988a Characteristics Percentage Age   15–19 13.6 20–24 24.5 25–29 25.3 30–34 18.8 35–39 11.2 40–44 6.6 Total 100.0 Marital Status   Never married 38.2 Married 52.3 Formerly Married 9.5 Total 100.0 Poverty Level   <150% 20.1 150–299% 23.2 >300% 56.6 Total 100.0 Race/ethnicity   White 75.8 Black 12.2 Hispanic 8.4 Other 3.6 Total 100.0   a   The denominator for these percentages is women who reported using reversible contraception. SOURCE: National Center for Health Statistics. Unpublished tables from the 1988 National Survey of Family Growth. Tables 1-1, 1-2, 1-4, and 1-6 for 1988. to say that method failures never occur because they do. Rather it is to suggest that some unintended pregnancies ascribed to method failure may in fact be due to user failure and even to nonuse. There is also no doubt that using many of the reversible contraceptive methods correctly and consistently can be very challenging. For example, Oakley (1994) has sketched the chain of events that using an oral contraceptive requires a woman to master: obtaining pills, taking them in the correct order,

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--> taking each pill within the appropriate time window, abstaining from sex or using a backup method when necessary, obtaining refills on time, stopping one cycle and starting the next at the right time, interpreting problems correctly (neither over-reacting nor under-reacting), and taking effective action to resolve problems (see Chapter 5 for more discussion of the skills required for contraceptive use). The point is that many reversible methods are difficult to use perfectly all of the time, and therefore user failure should be seen as reflecting both the skills of the user as well as the inherent complexity of many available reversible methods themselves. Recognizing these realities, researchers studying contraceptive failure rates often distinguish between typical use and perfect use, thus providing some context for separating mechanical failure from user foible. Perfect use reflects contraceptive use that is consistently performed according to the specified instructions; all pregnancies occurring in the presence of perfect use are classified as method failures. Typical use, on the other hand, reflects a combination of actual method failure and user failure—a more real-world, everyday measure. Rates of failure are substantially higher with typical use than with perfect use. Not surprisingly, in typical use, coitus-dependent methods are significantly less effective than coitus-independent methods, especially those that are longer-acting. For example, the first-year contraceptive failure rate for condoms and diaphragms ranges from 12 to 20 percent (Hatcher et al., 1994), and the 6-month failure rate of the female condom is estimated to be 12 percent (Trussell et al., 1994). By contrast, contraceptive implants and injections have less than a 1 percent failure rate (Ross, 1989; Hatcher et al., 1994). Overall, those reversible methods that are nearly impervious to user shortcomings are most effective in day-to-day life. Jones and Forrest (1992) computed failure rates of several commonly used methods based on the 1982 and 1988 NSFG. These rates, shown in Table 4-4, were calculated on the basis of the first 12 months of use, and therefore may not reflect failure rates over longer periods of time. The investigators suggest that rates of contraceptive failure may have increased during the 1980s, especially for some methods. Failure rates for oral contraceptives, for example, increased from 6 to 8 percent between 1982 and 1988—a trend that is particularly worrisome given the fact that under conditions of perfect use, oral contraceptives yield only about one pregnancy in 1,000 women in the first year of use. This increase can also be seen in less reliable methods; for example, the failure rate for periodic abstinence increased from 16 to 25 percent during the 1980s. It is important to emphasize that, given the imperfect array of contraceptives available to both men and women and the years of exposure to the risk of unintended pregnancy, some appreciable number of unintended pregnancies will inevitably occur over the life course. One simple computation suggests that this accumulates to a large risk over time. Ross (1989) offers the example of a young

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--> al., 1993). This increase may reflect deepening concern over HIV-AIDS transmission. Since 1988, there appears to have been no further growth overall in the use of condoms at first intercourse among men (Ku et al., 1993c; Pleck et al., 1993). Withdrawal is also a method frequently used early in a man's reproductive life span, although it is being reported less often in recent years. It is useful to note that withdrawal, although not very effective, is still much more effective than failing to withdraw altogether, because the 1-year pregnancy rate of withdrawal is 19 percent and the 1-year pregnancy rate of no contraception at all is 85 percent (Hatcher et al., 1994). Use of Male Methods by Married Men Although the role of men in providing contraceptive protection at first intercourse is somewhat well known, less attention has been paid to the use of male contraceptive methods by married men. Since nationally representative data about the contraceptive practices of married women were first collected in 1973, male partners have been found to provide at least one-fourth of the contraception that is reported. As measured at three points in time (1973, 1988, and 1990), condom use among married men has remained stable at 14 percent. Sterilization, however, rose from 11 to 19 percent between 1973 and 1990 (Mosher, 1990; Peterson, 1995). Although vasectomy is an important contraceptive method, few data are available in the literature to help provide an understanding of the dynamics of its use. Miller and colleagues (1991) report that married couples who are less traditional and more egalitarian are more likely to choose male over female sterilization; in addition, when the wife feels that communication between the spouses is effective, vasectomy is again more likely to be chosen over female sterilization. As shown in Table 4-5, there are also racial and ethnic differences in the reliance of women on male versus female sterilization. For example, very few minority women report that they rely on their partner's sterilization to protect them against unintended pregnancy. As noted earlier, vasectomy is a highly effective contraceptive method, but unfortunately, nearly 40 percent of men fail to return for a post-vasectomy semen analysis. If sperm are still present in the vas deferens of these men who lack follow-up care, they remain at risk of causing an unintended pregnancy for some time (J.M. Haws, pers. com., July 1994). Age and Condom Use Condom use has increased in the past decade, reaching especially high levels among adolescents. However, data from the 1991 Follow-up of the National

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--> Survey of Adolescent Males and the 1991 National Survey of Men suggest that condom use decreases as men grow older (see Figure 4-2) (Pleck et al., 1993). Although the measures are not completely comparable across the two data sets, there is clearly a negative association between condom use and age. Although older men are part of an earlier cohort who initiated sexual activity before the age of AIDS and safe sex, there are also indications that the decline in condom use reflects the maturation of relationships and the transition to female methods of contraception (including sterilization) that are often more effective in preventing pregnancy (Landry and Camelo, 1994). Even among adolescents aged 15 to 19, there appears to be a decrease in condom use by age, reflecting movement to female methods after initial sexual experiences during which condoms are often used. One study reports that 16-year-old men who are sexually active use condoms more than 19-year-olds (Sonenstein et al., 1989). Figure 4-3 provides an example of this by showing the contraceptive method used at last intercourse for sexually active adolescent men in 1988 and for the same young men nearly 3 years later, in 1991. Race, Ethnicity, and Condom Use Condom use varies by racial and ethnic affiliation. Black men are the most likely to report using condoms at all ages. Among adolescents, black men use condoms at higher rates than either Hispanic men or non-Hispanic white men (Pleck et al., 1991). The average percentage of times condoms were used increased among adolescent men of all ages between 1988 and 1991, but particularly among Hispanics (nearly 6 percent increase) and whites (nearly 5 percent increase) (Centers for Disease Control and Prevention, 1993). Nationally representative data about condom use among adult Hispanic men are not available. Although condom use among black adolescent men is higher at last intercourse than among white men of comparable age, condom use at first intercourse is lower. Since black men, on average, initiate sex about 1 year earlier than white men, and since earlier ages of first intercourse are associated with less use of contraception, some of the racial difference in condom use at first intercourse is attributable to differentials in age at initiation (Sonenstein et al., 1989). However, after age at initiation is controlled along with other confounding variables, being a young black man continues to be associated with lower condom use at first intercourse (Ku et al., 1993a).

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--> Figure 4-2 Condom use among men, by age, 1991. Source: Pleck JH, Sonenstein FL, Ku L. Changes in adolescent males' use of and attitudes toward condoms, 1988–1991. Fam Plann Perspect. 1993:25:106–110, 117. Socioeconomic Status and Condom Use Among adolescents, significant associations have been found in one study between socioeconomic measures and the use of effective contraception. However, the direction of the association was unanticipated by the researchers. Adolescent men with lower socioeconomic status were expected to report lower rates of effective contraceptive use, yet it was found that, net of other variables, use of effective contraception was higher among sexually experienced men living in neighborhoods with high poverty rates and lower among more affluent men (Ku et al., 1993b; Sonenstein et al., 1992). Multivariate analyses have not uncovered any systematic associations between the socioeconomic status of adolescent men and their use of condoms. Measures of family income, parental education, and welfare receipt are not significantly related to recent condom use among sexually experienced men (Pleck et al., 1991; Ku et al., 1992). By contrast, adult men with more education report greater condom use than those with less education (Tanfer et al., 1993).

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--> Figure 4-3 Form of contraception used at last intercourse as teen males grow older. Source: Pleck JH, Sonenstein FL, Ku L. Changes in adolescent males' use of and attitudes toward condoms, 1988–1991. Fam Plann Perspect. 1993:25:106–110, 117. Use of Dual Contraceptive Methods Given the appreciable failure rates of single reversible methods, it is important to consider the use of two methods simultaneously to prevent unintended pregnancy. Dual methods often involve the active participation of both male and female partners (particularly if one of the two methods chosen is a condom), and use of dual methods can expand the role of men in preventing unintended pregnancy. Depending on the combination of methods selected, the use of two methods simultaneously can also reduce the risk of STDs. For example, the use of two female methods, such as oral contraceptives and foam, provides more complete

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--> protection against unintended pregnancy than the use of either method alone. The use of both a female method and a condom, however, not only provides added protection against unintended pregnancy but is also a more effective way for women and men to protect themselves from the risk of contracting an STD. There is some evidence that the use of dual methods is increasing. For example, in 1979 a mere 3 percent of sexually active urban men aged 17–19 reported using both a condom and a female method of contraception simultaneously; this rate rose to 16 percent by 1988 (Zelnick and Kantner, 1980; Pleck et al., 1993). More recently, 25 percent of all women in the 1992 Ortho Birth Control Study reported using condoms concurrently with another method, and more than half of the women using less effective methods such as periodic abstinence reported using condoms as well (Forrest and Fordyce, 1993). Dual usage appears to have increased between 1992 and 1994; 46 percent of the women surveyed in the 1994 Ortho Birth Control Study reported using condoms in addition to their primary contraceptive. Among this group of dual-method users, nearly half claim that they are doing so solely for the prevention of unintended pregnancy (Ortho Pharmaceutical Company, 1994). Sexually Transmitted Diseases As just noted, sexual activity can result not only in unintended pregnancies but also in the transmission of STDs. However, there are other links between unintended pregnancy and STDs as well: many risk factors for STDs and unintended pregnancy are the same; unintended pregnancy precludes the opportunity to resolve an STD before conception; and the desire to achieve protection against both STDs and unintended pregnancy may influence the choice of contraceptive methods, including dual methods. STDs are spread by the transfer of infectious organisms from one person to another during sexual contact. Although it is difficult to calculate the prevalence of STDs, there are currently an estimated 56 million cases of viral STDs in the United States, and approximately 12 million new cases of both viral and nonviral STDs occur annually (Centers for Disease Control and Prevention, 1993). Two-thirds of new cases occur to people under 25 years of age, a cohort that also contributes heavily to unintended pregnancy, and approximately 3 million adolescents acquire an STD every year (Donovan, 1993). More than 20 organisms and syndromes are now recognized as STDs, including curable nonviral infections (e.g., chlamydia, gonorrhea, syphilis, or chancroid) and viral infections that are not curable, but are treatable (e.g., human papillomavirus or genital herpes) or preventable (e.g., hepatitis B virus through the hepatitis B vaccine) (Centers for Disease Control and Prevention, 1993; Alan Guttmacher Institute, 1994). Many of these STDs, if left untreated, can result in serious health repercussions not only for the man or woman who is infected, but also for a developing fetus.

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--> Of great concern at present is HIV, a relatively new viral STD. HIV infection results in AIDS. AIDS is currently both incurable and fatal, although antiretroviral therapies are available for treatment. Nearly 1 million people in the United States were estimated to be infected with HIV in 1993—approximately 1 in 100 men and 1 in 800 women (Centers for Disease Control and Prevention, 1993). Perinatal transmission of HIV occurs in approximately 20 to 30 percent of births to infected mothers (Hatcher et al., 1994). Nearly 80 percent of AIDS cases are to people between the ages of 20 and 44, the prime childbearing years (Centers for Disease Control and Prevention, 1993). The risk factors for STD infection overlap those for unintended pregnancy. For example, the risk of both unintended pregnancy and STD infection is greater for women and men who initiate sexual intercourse at lower ages, for those who have a greater number of both current and lifetime sexual partners, and for those who have a higher frequency of intercourse (Centers for Disease Control and Prevention, 1993; see also Kost and Forrest, 1992). One particularly unfortunate consequence of unintended pregnancy is that it often precludes the chance to resolve an STD before conception or to consider avoiding pregnancy altogether because of the presence of an incurable STD that poses serious risks to a fetus, such as HIV-AIDS (Chapter 3 includes additional discussion of other opportunities for health promotion that are missed because a pregnancy is unintended). STDs left untreated in pregnant women can result in premature delivery, infection in the newborn, or infant death (Centers for Disease Control and Prevention, 1993). Finally, because sexual activity often carries a risk of both unintended pregnancy and STD transmission, the choice of contraceptive methods has become more complicated. As suggested in the previous section on dual-method use, it is often necessary to use more than one method to prevent both STDs and unintended pregnancy. But individuals and couples may attach differing priorities to these two goals, and their priorities may change over time and across relationships. Moreover, couples may find it difficult to use two methods simultaneously. In this era of AIDS and the increasing incidence of other STDs, research on the determinants of contraceptive behavior has yet to take into consideration this complicated calculus. Two notable exceptions are the research by Kost and Forrest (1992), in which contraceptive decision-making was examined from the perspective of preventing both pregnancy and STDs, and the research by Landry and Camelo (1994), who reported on discussions with young, unmarried people about their use of contraception in both preventing pregnancy and avoiding STDs. In this context, it is important to note that although condoms are the most effective contraceptive method for reducing STD transmission, other methods can also provide some protection against selected pathogens (Table 4-8). Unfortunately, no single method at present provides maximum protection against both unintended pregnancy and all STDs.

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--> TABLE 4-8 Effects of Contraceptives on Bacterial and Viral STDs Contraceptive Methods Bacterial STD Viral STD       Condoms Protective Protective       Spermicides with nonoxynol-9 Protective against gonorrhea and chlamydia Undetermined in vivo       Diaphragms Protective against cervical infection; associated with vaginal anaerobic overgrowth Protective against cervical infection       Oral contraceptives Associated with increased cervical chlamydia; protective against symptomatic pelvic inflammatory disease Not protective       IUDs Associated with pelvic inflammatory disease in first month after insertion Not protective       Rhythm method Not protective Not protective   SOURCES: Ehrhardt AA, Wasserheit JN. Age, gender, and sexual risk behaviors for sexually transmitted diseases in the United States. In Research Issues in Human Behavior and Sexually Transmitted Diseases in the AIDS Era. Wasserheit JN, Aral SO, Holmes KK, Hitchcock PJ, eds. Washington, DC: American Society for Microbiology; 1991. Hatcher RA, Trussell J, Stewart F, et al. Contraceptive Technology, 16th revised ed. New York, NY: Irvington Publishers, Inc.; 1994: Table 4-2.

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--> Conclusion Several interesting conclusions emerge from an exploration of the patterns of contraceptive use as they relate to unintended pregnancy. First, women who report using reversible means of contraception (a large group) and women who report using no contraception at all despite having no clear intent to become pregnant (a small group) contribute roughly equally to the pool of unintended pregnancies. That is, about half of all unintended pregnancies derive from women who are not actively seeking pregnancy and who are using reversible contraception; the other half derive from women who are also not actively seeking pregnancy but who nonetheless are not using contraception. Many women and couples who are not intending to become pregnant move between these two groups, sometimes practicing contraception and sometimes not. Contraceptive use has increased in recent years, primarily because of a rise in contraceptive female sterilization; moreover, the participation of men in providing reversible contraceptive protection is increasingly important, particularly at first intercourse. Nonetheless, unintended pregnancy continues to occur among couples who use reversible methods of contraception because many reversible methods are of only limited effectiveness even under conditions of perfect use, and because of the misuse of these same methods, some of which can be explained by the difficult compliance regimens that many require. Overall, coitus-dependent methods are much more susceptible to user failure than are long-acting coitus-independent methods, and thus couples relying on coitus-dependent methods are at greater risk of unintended pregnancy. To reduce the risk of unintended pregnancy to the bare minimum, short of sterilization, couples are increasingly using two methods at once. Depending on which two methods are selected, dual-method use can help to reduce the risk of both STD transmission and unintended pregnancy. Indeed, the whole process of method selection has been complicated by the increasing presence of STDs and the importance of sexually active couples protecting themselves against both threats. References The Alan Guttmacher Institute. Sex and America's Teenagers. New York, NY; 1994. The Alan Guttmacher Institute. Norplant: Opportunities and Perils for Low-Income Women. Special Report No. 2. New York, NY; 1993. Centers for Disease Control and Prevention. Division of STD/HIV Prevention Annual Report. Atlanta, GA; 1993. Donovan P. Testing Positive: Sexually Transmitted Disease and the Public Health Response. New York, NY: The Alan Guttmacher Institute; 1993.

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