Contraception in the United States
Fertility decreases as societies become more affluent. This decrease is a response to the use of contraception and abortion. During her reproductive lifespan, the average !Kung woman, a member of an African tribe of hunter-gatherers, experienced 15 years of lactational amenorrhea, 4 years of pregnancy, and only 48 menstrual cycles.1 In contrast, a modern urban woman will experience 420 menstrual cycles. Contemporary women undergo earlier menarche and start having sexual intercourse earlier in their lives than in the past. Even though breastfeeding has increased in recent years, its duration is relatively brief and its contribution to contraception in the developed world is trivial. Therefore, it is more difficult today to limit the size of a family unless some method of contraception is utilized.
Today, more women younger than age 25 in the United States become pregnant than do their contemporaries in other Western countries.2,3,4 The U.S. teenage pregnancy rates are twice as high as those in England, Wales, and Canada and eight times as high as those of the Netherlands and Japan.5 The differences disappear almost completely after age 25. This is largely because American men and women after age 25 utilize surgical sterilization at a high rate.
It is not true that young American women want to have these higher pregnancy rates. About 82% of all pregnancies among American teenagers are unintended.6 Increasing effective contraceptive use among young Americans began to have an impact in 1991. In the 1990s, the teenage pregnancy rate reached the lowest rate since estimates began in 1976, a 21% decline from 1991 to 1997 for teenagers 15 to 17 years and a 13% decline for older teenagers.7 Overall, there was a 17% decline in teenage birth rates and a 12.8% decline in teenage-induced abortions from 1991 through 1999. From 1995 to 2002, 14% of the decline in teen pregnancy was a consequence of decreased sexual activity among U.S. teenagers; however, 86% of the decline was attributed to an increase in the use of effective contraception.8 In 2004, the proportion of induced abortions in the United States obtained by teens reached a low of 17%.9
After a 14-year 34% decline, birth rates for teenagers began to increase in 2005, the first increase since 1991. The rate increased 5% between 2005 and 2008.10 There is appropriate concern that this increase reflects difficulties in contraceptive access, affordability, and correct use. In addition, in recent
years, fewer teens have received instruction regarding contraception.11 The evidence overwhelmingly indicates that abstinence programs have not had a positive impact on teen sexual behavior, including the delay of the initiation of sex or the number of sexual partners.12 In contrast, comprehensive sex education programs that include contraception are effective and do not increase the frequency of sex or hasten the initiation.13
years, fewer teens have received instruction regarding contraception.11 The evidence overwhelmingly indicates that abstinence programs have not had a positive impact on teen sexual behavior, including the delay of the initiation of sex or the number of sexual partners.12 In contrast, comprehensive sex education programs that include contraception are effective and do not increase the frequency of sex or hasten the initiation.13
Nearly half of all pregnancies (49%) in the United States are unplanned, and about 40% of these are aborted.6,14 American teenagers abort about 34% of their pregnancies, and this proportion is similar to that seen in other countries.5 But older American women, aged 20 to 34, have the highest proportion of pregnancies aborted compared with other countries, indicating that an unappreciated, but real, problem of unintended pregnancy still exists beyond the teenage years. In fact, American women older than age 40 have had for the last 2 decades a high ratio of abortions per live births, a ratio very similar to that of teenagers.9
Delaying marriage prolongs the period in which women are exposed to the risk of unintended pregnancy. This, however, cannot be documented as a major reason for the large differential between young adults in Europe and the United States. The available evidence also indicates that a difference in sexual activity is not an important explanation. The major difference between American women and European women is that American women under age 25 are less likely to use any form of contraception. Significantly, the use of oral contraceptives (the main choice of younger women) is lower in the United States than in other countries.
Why are Americans different? The cultures in areas such as the United Kingdom and the Scandinavian countries are certainly very similar with similar rates of sexual experience. A major difference must be attributed to the availability of contraception. In the rest of the world, contraceptive services can be obtained from more accessible resources and relatively inexpensively. Major American problems are the enormous diversity of people and the unequal distribution of income in the United States. These factors influence the ability of our society to effectively provide education regarding sex and contraception and to effectively make contraception services available.
In 1966, a report from NASA placed our technological achievements into historical perspective.15 Eight hundred lifespans can bridge more than 50,000 years. But of those 800 people
650 spent their lives in caves,
only the last 70 had a truly effective means of communication,
only the last 6 saw the printed word,
only the last 4 could measure time with precision,
only the last 2 used an electric motor,
and the majority of items which make up our current world were developed within the lifespan of the 800th person.
The era of modern contraception dates from 1960 when intrauterine devices (IUDs) were reintroduced and oral contraception was first approved by the
U.S. Food and Drug Administration. For the first time, contraception did not have to be a part of the act of coitus. However, national family planning services and research were not funded by the U.S. Congress until 1970, and the last U.S. law prohibiting contraception was not reversed until 1973.
U.S. Food and Drug Administration. For the first time, contraception did not have to be a part of the act of coitus. However, national family planning services and research were not funded by the U.S. Congress until 1970, and the last U.S. law prohibiting contraception was not reversed until 1973.
Contraception is not new; but its widespread development and application are new. It is in the latest tick of the Earth’s time clock that safe control of fertility is now possible. This book is dedicated to that end. This chapter will present an overview of the efficacy of contraceptive methods, a summary of contraceptive use in the United States and the world, and a brief look at the future.
Efficacy of Contraception
A clinician’s anecdotal experience with contraceptive methods is truly insufficient to provide the accurate information necessary for patient counseling. The clinician must be aware of the definitions and measurements used in assessing contraceptive efficacy and must draw on the talents of appropriate experts in this area to summarize the accurate and comparative failure rates for the various methods of contraception. The publications by Trussell et al.,16,17,18,19,20 summarized below, accomplish these purposes and are highly recommended.
Definition and Measurement
Contraceptive efficacy is generally assessed by measuring the number of unplanned pregnancies that occur during a specified period of exposure to and use of a contraceptive method. The two methods that have been used to measure contraceptive efficacy are the Pearl index and life-table analysis.
The Pearl Index
The Pearl index, created by Raymond Pearl in 1933, is defined as the number of failures per 100 woman-years of exposure.21 The denominator is the total months or cycles of exposure from the onset of a method until completion of the study, an unintended pregnancy, or discontinuation of the method. The quotient is multiplied by 1,200 if the denominator consists of months or by 1,300 if the denominator consists of cycles.
With most methods of contraception, failure rates decline with duration of use. The Pearl index is usually based on a lengthy exposure (usually 1 year) and, therefore, fails to accurately compare methods at various durations of exposure. This limitation is overcome by using the method of lifetable analysis.
Life-Table Analysis
Life-table analysis calculates a failure rate for each month of use. A cumulative failure rate can then compare methods for any specific length of exposure. Women who leave a study for any reason other than unintended pregnancy are removed from the analysis, contributing their exposure until the time of the exit.
Contraceptive Failures
Contraceptive failures do occur and for many reasons. Thus, “method effectiveness” and “use effectiveness” have been used to designate efficacy with correct and incorrect use of a method. It is less confusing to simply compare the very best performance (the lowest expected failure rate) with the usual experience (typical failure rate) as noted in the table of failure rates during the first year of use. The lowest expected failure rates are determined in clinical trials, in which the combination of highly motivated subjects and frequent support from the study personnel yields the best results. Contraceptive typical failure rates have been estimated using the data from the 1995 and 2002 U.S. National Survey of Family Growth, correcting for the underreporting of induced abortion.19,20,22
The 2002 estimates of failure were not significantly different compared with the previous estimates from the 1995 national survey. Women over the age of 30 were less likely to experience failure than young women; teens were more than twice as likely to experience a failure than older women. Hispanic women and even more so, black women, experienced higher failure rates. Groups that were less likely to experience contraceptive failure were women who did not intend to have a subsequent birth and women who had no previous births. Married women experienced the lowest failure rates and cohabiting women the highest. The most important determinants of pill failure, therefore, were age, intention toward a future birth, parity, and marital status. Interestingly, once these factors were accounted for, duration of use, race, ethnicity, and poverty status no longer affected the risk of pill failure. The same factors influence condom use, but when corrected for these factors, race, ethnicity, and poverty affected the risk of condom failure.
This is a subject of great interest because the rate of unintended pregnancies in the United States continues to be high. About one half (over 3 million) of all pregnancies in the United States are unintended, and in 2002, about 53% of those occurred in women using a method of contraception.6,14,23 Here is a more striking statistic: one of every two American women aged 15 to 44 has experienced an unintended pregnancy.14
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