Nonmarital childbearing in the United States, 1940-99.

OBJECTIVES: This report presents information on trends and variations in nonmarital childbearing in the United States and includes information on the factors that have contributed to the recent changes. Data are presented for 1940-99 with emphasis on the trends in the 1990's. METHODS: Data in this report are presented on a variety of measures of nonmarital childbearing, including numbers, rates, and percent of births to unmarried women. Most of the data is from the National Vital Statistics System. Additional data explaining the trends shown are from the National Survey of Family Growth, the U.S. Census Bureau, and other national surveys. Data are presented and interpreted principally in charts and related tables. RESULTS: After rising dramatically during the half century from 1940 to 1990, out-of-wedlock childbearing leveled off, or slowed its rate of increase, in the 1990's. Many factors contributing to the long-term changes as well as more recent trends are described. These include changes in marriage patterns, sexual activity, contraceptive use, and abortion. The experience of the United States is put into context with data on nonmarital childbearing for other industrialized countries. Possible future trends in out-of-wedlock births are considered in the context of current population and birth patterns.

Intended pregnancies and unintended pregnancies: distinct categories or opposite ends of a continuum?

PIP: This article examines the entity of intended and unintended pregnancy. Results provided a strong evidence of bias. The reason for this bias may be due to an increased pressure for women to give a socially desirable response. This problem suggested three potential courses of action, such as: a combination of traditional cross-sectional studies with intendedness and wantedness values, improvement of retrospective measurements, and development of model predictors of reporting bias. With regards to the affective dimension, the positive and negative extremes may not be located on the same continuum; that is, positive and negative feelings coexist, hence producing ambivalence. Consequently, researchers should continue their efforts to expand approaches to these concepts and improve the ways of measuring them in future studies.^ieng

Understanding U.S. fertility: continuity and change in the National Survey of Family Growth, 1988-1995.

About 50 studies based on the 1988 National Survey of Family Growth (NSFG) and a telephone reinterview conducted with the same women two years later provide continuing information about the fertility and health of American women. Among the findings of these studies are that black women have almost twice as many pregnancies as do white women (5.1 vs. 2.8), with nearly all of the difference being unintended pregnancies. Unwanted births increased between 1982 and 1988, particularly among less-educated, poor and minority women. This increase in the proportion of unwanted births may have prompted the increase in female sterilization among these groups. Concern with the AIDS epidemic led to increases in condom use between 1982 and 1990, especially among the partners of teenagers and college-educated women. Rates of teenage pregnancy were fairly stable during the period 1980-1988, as increases in the proportion of teenagers having intercourse were offset by increases in condom use. Rates of infertility did not change significantly in the 1980s, but because of delayed childbearing and the aging of the baby-boom cohort, the number of older childless women increased substantially. The 1995 NSFG was redesigned in a number of ways in order to answer a new generation of questions about fertility and women's health in the United States.

PIP: US fertility surveys were conducted during 1955-70 and were formally instituted under the National Survey of Family Growth (NSFG) during 1973-88. Telephone reinterviews were conducted in 1990. This paper reviews findings from about 50 studies based on the NSFG in 1988 and 1990 and identifies changes in survey data and methods. Findings pertain to variables on intercourse and union formation, conception and contraceptive use, gestation, and fertility-related issues. Policy issues are discussed that relate to adolescent pregnancy, adoption, use of family planning services, maternal-child health, and HIV and sexually transmitted disease prevention. Cycle 5, which is scheduled for the NSFG in 1995, will be redesigned to accommodate policy needs. Changes will include increased coverage of explanatory patterns, such as family background, and inclusion of event histories for cohabitation and marriage, sexual partnerships, work, education, and past living arrangements with parents and grandparents. Measurement will improve for fertility-related variables that may explain unintended pregnancy. Such measures will cover consistency of contraceptive use, characteristics of sexual partners, women's attitudes about their pregnancies, family planning and infertility services, and other health care use measures. The 1995 survey will make a qualitative shift to computer-assisted personal interviewing. Abortion reporting will be more complete, due, in part, to the use of audio-assisted computer interviewing. Data collection occurred during January-October 1995. Trends during 1988-90 include higher rates of cohabitation, and large racial differences in the proportions who never married. There were increases in premarital sex behavior and in births to unmarried women. Perception of economic opportunity was associated with a greater likelihood of contraceptive use at first intercourse. Female sterilization was the leading method among women aged 30-34 years. First year failure rates were higher among low income women. Infertility and teenage pregnancy remained stable. Unintended fertility, which was strongly related to low education and income, older age, and Black race, was very high at 57% of all pregnancies.

Relinquishment of premarital births: evidence from national survey data.

According to 1982 and 1988 NSFG data, unmarried white women are far less likely than they were in the early 1970s to place their children for adoption. The levels of relinquishment among black women have remained low throughout this period, and relinquishment among Hispanic women may be virtually nonexistent. Multivariate analysis of the determinants of relinquishment among unmarried non-Hispanic white women suggests that having a well-educated mother, being in school at the time of conception, having no labor force experience, and being older are positively associated with placing a child for adoption. Sons were found to be less likely to be relinquished than daughters.

PIP: Researchers analyzed data from the 1982 and 1988 cycles of the National Survey of Family Growth (NSFG) to look at trends in the giving up of children of unmarried women in the US and to examine factors which are linked to the decision to put a child up for adoption. Since the numbers of black and Hispanic women who relinquished a child were so small, the final analysis only included white women. Overall relinquishment fell over time, especially during the 1970s which may have been due to the increased access to abortion in the US in the early 1970s. A higher percentage of women relinquished their children before 1973, during 1973-1981, and 1982-1988 (19.3, 7.6, and 3.2 respectively) than black women (1.5, 0.2, and 1.1 respectively). Hispanic women rarely relinquished their children. Significant factors that influenced unmarried white women to place a child for adoption included month and year of birth (p.01), maternal education (p.01), and opportunity costs of becoming a parent. The most significant opportunity cost that played a role in decision making was conception occurred when the mother was not in school (p.01). The older the woman at time of birth the more likely she would relinquish the child (p,05). Further mother that had paid employment before birth tended to place the child for adoption (p,05). Women with sons were less likely to relinquish them than those with daughters (p.05). The authors suggested that these results be compared with those on decision making involving abortion. Specifically they should look at all behaviors resulting in pregnancy resolution decision as well as the cost and benefits of parenthood and its alternatives. Moreover they should conduct research that assesses attitude toward adoption, since attitude toward abortion among different population groups is well known.

What do women use when they stop using the pill?

Current use of oral contraceptives among currently married women aged 15-44 declined from 25 percent to 13 percent between 1973 and 1982, while ever-use increased from 60 percent to 80 percent. By 1982, the pill appeared to be used mainly to delay first pregnancies, secondarily to space subsequent conceptions, and only rarely as a means of ending childbearing. Most women who had stopped using the pill by 1982 had done so on their own initiative: Only about one-third had been advised by a doctor to discontinue use. Virtually all former users gave some physical problem connected with pill use as a reason for quitting the method. At the time they quit, former users had been taking the pill for an average of 3.2 years. The decline in current use of the pill during the 1970s coincided with a marked increase in contraceptive sterilization, but was not the result of a direct switching from the pill to sterilization by individual women. Only 21 percent of women who quit the pill chose sterilization as their next method. The majority--60 percent--switched to nonpermanent methods, the condom being the most popular in all age-groups; the proportions selecting the condom as their next method ranged from 20 percent of 15-19-year-olds to 12 percent of 30-44-year-olds. Nineteen percent of former pill users did not adopt any method after discontinuing the pill.

PIP: Current use of oral contraceptives (OC) among currently married US women aged 15-44 declined from 25% to 13% between 1973 and 1982, while ever-use increased from 60 to 80%. By 1980, the pill appeared to be used mainly to delay 1st pregnancies, 2nd to space subsequent conceptions and only rarely as a means of ending childbearing. Most women stopped at their own initiative, 1/3 were advised by their physicians. Almost all former users (who as a group had been taking OCs for an average of 3.2 years) gave a physical problem connected with quitting. 21% of the women who quit OCs chose sterilization as their next method. 60% switched to nonpermanent methods, with the condom being most popular in all age groups. 19% of former users did not adopt any method after discontinuing OCs. Over 1/2 adopted a new method without any break in contraceptive use. 20% had some break in use but were not exposed to the risk of unintended pregnancy. 27% were exposed and went unprotected for some time after quitting. By 1982 the proportion of women who switched to sterilization rose to 30%, while those using nonpermanent methods fell to 29%. Among white married women who stopped OC use in 1979 or later, 6% of those who had switched to IUDs or sterilization had unintended pregnancies, 23% of those who chose periodic abstinence or withdrawal became pregnant. 10% who adopted their next method within the same month became pregnant as compared to 26% who had a break in contraceptive use.

First premarital contraceptive use: United States, 1960-82.

This study shows the first national estimates of trends and differentials in first contraceptive use for a national sample of all women. Only 47 percent of women aged 15-44 in 1982 (or their partners) used a method at first premarital intercourse. The leading method at first intercourse was the condom, followed by the pill and withdrawal. The percentage using a method increased from the early 1960s to the late 1970s, because of increases in use of the pill and withdrawal. However, in the early 1980s, use at first intercourse increased sharply because of an increase in use of the condom. The proportion who used a method at first intercourse varied from 22 percent among Hispanic women to 74 percent among Jewish women; it was higher among white than black women, and higher in higher socioeconomic categories. After first intercourse, contraceptive use did not vary significantly by socioeconomic characteristics. While the condom was the leading method at first intercourse, women who practiced contraception for the first time after first intercourse typically used the pill.

Understanding U.S. fertility: findings from the National Survey of Family Growth, Cycle III.

PIP: The 1st overview of findings from Cycle III of the National Survey of Family Growth, the latest of 7 such surveys of US fertility since 1955 and the 1st to cover all women of childbearing age in the conterminous US is presented. Interviews between August 1982 and February 1983 with 7969 women, representative of 54 million women aged 15-44, reveal that sterilization is now the leading contraceptive method in the US, used by 33% of all contraceptors in 1982 (22%, female sterilization; 11% male sterilization), followed by the pill (29%), condom (12%), diaphragm (8%), and IUD (7%). Linked to this is the continuing decline in unwanted births since the baby boom peak in 1957, which accounted for nearly 1/2 of the drop between 1973 and 1982 in ever-married women's children ever born, from 2.2 to 1.9/woman. However, births conceived sooner than planned increased slightly among younger married women, probably due to the large drop in pill use since 1973 and increased use of the less effective diaphragm and condom among couples still intending to have more children. Black women are now more likely than white women to use the most effective female methods: female sterilization, pill, and IUD. Only 45% of women aged 15-44 in 1982 had used a contraceptive method at 1st intercourse. 4 out of 5 women married for the 1st time between 1975 and 1982 had intercourse before marriage. However, premarital sexual activity may be leveling off among white teenagers after a steep rise since the early 1970s and declining moderately among black teenagers. 16% of 1st marriages among ever-married women aged 15-44 in 1982 had been dissoved within 5 years, mostly by divorce or separation. 59% of black women with children in 1982 had their 1st birth before marriage, compared to 11% of white mothers. The proportion of babies who were breastfed more than doubled between 1970-71 and 1980-81, from 24 to 53%.^ieng

Contraceptive practice among American women, 1973-1982.

During the decade 1973-1982, use of oral contraceptives declined sharply among wives aged 15-44, although the total number of pill users did not decrease after 1979. This drop occurred in all groups of wives examined. At the same time, the prevalence of female contraceptive sterilization rose sharply; this increase occurred mainly among wives aged 35 and older and, of course, among all wives intending no more children. Among other subgroups of married women, the fall in pill use was complemented by a smaller rise in the use of barrier methods--the condom and diaphragm, in particular. The contraceptive status and method choices of never-married and previously married women differed sharply from those of wives as of 1982. Sexually active never-married women were less likely than married women to practice contraception and were more likely to choose the pill when they did. Previously married women were also less likely than wives to practice contraception but, when using a method, were more likely than either never-married or currently married users to depend on one of the more effective methods--sterilization, the pill or the IUD.

Childlessness in the United States: estimates from the National Survey of Family Growth.

PIP: Using a representative sample of about 17,000 ever married women 15 to 44 years of age, this article presents national estimates of the prevalence and correlates of voluntary, involuntary, and temporary childlessness in the United States. These three groups of childless couples are compared with the parents of small planned families and other parents on a number of social, economic, marital, and family characteristics. When viewed cross sectionally, voluntarily childless couples constitute between 1.3% and 1.8% of currently married couples, depending on the definitions used. They are a distinctive but rare population. Their future prevalence depends primarily on the decisions of the large group of temporarily childless couples.^ieng

Recall and reliability of interview data from older women.

Retrospective fertility histories were collected from a purposive sample of 211 white, ever-married women, residing in four metropolitan areas of the USA and belonging to the birth cohorts of 1901-1910. At the time of interview, these women were aged 66 to 76. A random sample of 50 of the original respondents was reinterviewed by telephone on selected topics from the questionnaire. Responses to questions on dates and numbers of marriages, as well as births and other fertility events were coded to show whether the responses were exact, estimated by the respondent, or calculated by the editors. Respondents provided exact answers to an average of 90% of the questions they were asked. Reliability ratios, which were calculated for the above variables as well as ever-use of contraceptive methods, were comparable with those observed in previous studies of women in the childbearing years.

Selection of MEDLINE contents, the development of its thesaurus, and the indexing process.

The operation of MEDLINE requires three ongoing activities by persons having subject matter knowledge. These are literature selection, thesaurus maintenance and indexing. MEDLINE is intended to give access to the most generally useful biomedical literature rather than to provide indiscriminate comprehensive coverage. Literature is selected with the guidance of a group of health-science educators, editors and librarians who review periodicals under consideration for inclusion and re-evaluate those that are already regularly indexed. The MeSH thesaurus provides the descriptors that are used for subject indexing. Its hierarchical structure facilitates both general and specific searching. The appearance of new concepts and terminology in the literature requires a dynamic MeSH, but MeSH changes may complicate the process of searching backward in time. Maintaining MeSH requires finding a balance between the need for adaptability and the need for stability. Quality indexing requires accuracy and consistency in the assignment of subject headings. To this end, indexers receive didactic training plus practice under supervision. Precedents for indexers are detailed in an extensive Indexer's Manual and in MeSH annotations. Work of all indexers is reviewed on at least a sampling basis, and special sessions are held each year to familiarize indexers with MeSH changes.