What’s happening to the age at first birth in the United States? A study of recent cohorts

This paper analyzes cross-cohort trends in the age pattern of women at first birth in the United States. The analysis involves fitting the Coale-McNeil marriage model to the age distribution of first birth frequencies for a number of recent white and nonwhite cohorts. Methodologically, the results (a) provide support for the application of the Coale-McNeil marriage model to first birth data, and (b) demonstrate the ability of the model to accurately project first birth fertility for cohorts which have yet to complete their childbearing years. Substantively the results indicate (a) that the proportion of women who will never have a first birth is increasing across cohorts and can be expected to be as high as .25 and .20 for recent white and nonwhite cohorts respectively; (b) that recent nonwhite cohorts have an appreciable number of first births at earlier ages than their white counterparts, as well as a lower mean age at first birth and increasingly less dispersion (across cohorts) in their age at first birth; and (c) that the mean age at first birth and the proportion of first births occurring between ages 25 and 34 is increasing across cohorts of white women but is stable across cohorts of nonwhite women.     

Age at last birth and its components

This paper examines the ways in which the behavior of twentieth century cohorts of American women changed simultaneously in the three components of fertility that determine age at last birth--age at first birth, spacing between subsequent births, and parity progression ratios of subsequent births--to produce changes in the timing of the completion of childbearing. It decomposes changes in the mean age at last birth among cohorts and between whites and nonwhites to changes in these three components. To perform these analyses, we developed and applied a method to estimate the distributions and means of ages and last births, birth intervals, and parity progression ratios from age- and parity-specific fertility rates available from vital statistics data. Results show that the cohorts increased and decreased their age at first birth, birth intervals, and parity progression ratios of lower and higher birth orders in almost every possible combination so as to achieve a relatively young age at final birth.     

Proximate determinants of Philippine fertility: 1983 levels and patterns

Data from the 1983 National Demographic Survey are used to analyze the proximate determinants of Philippine fertility in each of the 3 stages of family formation and to identify all of the direct and indirect factors affecting fertility levels and trends. 10,843 ever-married women and 12,771 children were included. The analysis pertains first to the starting patterns of family formation, the age at first birth, and the proximate determinants (age at menarche, age at first marriage/union, conception before first birth, fetal wastage first birth, interval between first marriage and first birth). Further analysis examines birth spacing patterns including the postpartum nonsusceptible period, the exposure interval and stopping patterns. Almost all births occur within marriage, and childbearing begins late at 22.5 years. However, 15.4% of first births are conceived premaritally. The mean age at first birth increases from younger to older cohorts. Urban women were slightly older (23.0 years) at the birth of their first child. Those with education below the 4th grade had first births 3.5 years earlier. Contraceptive use was low at 1.8% before first birth. Younger cohorts were more likely to use birth control and urban wives were more likely to use it than rural wives. 6.4% reported a first pregnancy ending in nonlive births, which were primarily spontaneous abortions (5.2%), stillbirths (1.0%), and induced abortions (.2%). 5.8% report never having been pregnant and 1.1% never having given birth to a live-born child. 20.4% were childless between the ages of 15-24 years, and 4.6% between 25-34 years. Childlessness was slightly higher among urban women (7.1%) than rural women (6.7%). A decreasing age at menarche has appeared; i.e., 13.6 years for the cohort 15-24 years, and 14.0 for the oldest cohort. By age 15, 82.9% had begun menstruating. The mean age at marriage is early at 20.7 years, and older cohorts tended to marry later at 21.4 years. Urban women marry a year later (21.4 years) than rural women. Lower educated women marry 4 years earlier. The mean length between first marriage and first birth was 18.4 months. In the younger cohorts, spacing patterns are shorter. Postpartum susceptibility is short. Return to sexual relations after a birth occurred at 2.8 months. The exposure time required to conceive is fairly long at 16.6 months and is attributed to contraceptive use, since coital frequency is high and temporary separation is infrequent. The average age at last birth is late at 37.6 years.     

Age at marriage and timing of the first birth

Summary An attempt has been made to measure the effect of age at marriage of brides on the timing of the first birth. In Australian vital statistics, first nuptial confinements have been tabulated by age of mothers and by single years of marriage duration in single months for the first two years and by single years for all other durations since 1916. A simple technique has been used to link such data with marriage cohorts. The study briefly reviews the prevailing patterns of the timing of first births by mothers' age at marriage and changes in this pattern since the marriages of the 1925/9 period. The analysis shows that after a period of relative stability of family formation patterns in the 1950s and early 1960s, women married in the late 1960s started postponing the first birth beyond the first two years of marriage. It is suggested that a fraction of the decline in total births recorded in Australia since 1972 can be attributed to the postponement of first nuptial confinements by women married in the late 1960s and early 1970s.     

Does It Matter What She Wants? The Role of Individual Preferences Against Unmarried Motherhood in Young Women’s Likelihood of a Nonmarital First Birth

Most young people in the United States express the desire to marry. Norms at all socioeconomic levels posit marriage as the optimal context for childbearing. At the same time, nonmarital fertility accounts for approximately 40 % of U.S. births, experienced disproportionately by women with educational attainment less than a bachelor’s degree. Research has shown that women’s intentions for the number and timing of children and couples’ intent to marry are strong predictors of realized fertility and marriage. The present study investigates whether U.S. young women’s preferences about nonmarital fertility, as stated before childbearing begins, predict their likelihood of having a nonmarital first birth. I track marriage and fertility histories through ages 24–30 of women asked at ages 11–16 whether they would consider unmarried childbearing. One-quarter of women who responded “no” in fact had a nonmarital birth by age 24–30. The ability of women and their partners to access material resources in adulthood were, as expected, the strongest predictors of the likelihood of nonmarital childbearing. Nonetheless, I find that women who said they would not consider nonmarital childbearing had substantially higher hazards of fertility postponement and especially of marital fertility, even after controlling for race/ethnicity, mother’s educational attainment, family of origin intactness, self-efficacy and planning ability, perceived future prospects, and markers of own educational attainment and work experience into early adulthood.     

The Effect on Fertility of the 2003–2011 War in Iraq

This article provides the first detailed account of recent fertility trends in Iraq, with a particular focus on the changes resulting from the 2003–2011 war and the factors underlying them. The study is based on retrospective birth history data from the 2006 and 2011 Iraq Multiple Indicator Cluster Surveys (I‐MICS). Estimates from the two surveys indicate that total fertility remained stable from 1997 to 2010, at about 4.5 children per woman. However, examination of the age patterns of fertility reveals an abrupt shift in the timing of births, with adolescent fertility rising by over 30 percent soon after the onset of the war. A decomposition analysis shows that the rise in early childbearing is due to an increased prevalence of early marriage among less‐educated women. The prevalence of early marriage and childbearing among women with secondary or higher education is relatively low and has not increased after 2003.     

What are the determinants of delayed childbearing and permanent childlessness in the United States?

This paper presents estimates of delayed childbearing and permanent childlessness in the United States and the determinants of those phenomena. The estimates are derived by fitting the Coale-McNeil marriage model to survey data on age at first birth and by letting the parameters of the model depend on covariates. Substantively, the results provide evidence that the low first birth fertility rates experienced in the 1970s were due to both delayed childbearing and to increasing levels of permanent childlessness. The results also indicate that (a) delayed childbearing is less prevalent among black women than among nonblack women; (b) education is an important determinant of delayed childbearing whose influence on this phenomenon seems to be increasing across cohorts; (c) education is positively associated with heterogeneity among women in their age at first birth; (d) the dispersion of age at first birth is increasing across cohorts; (e) race has an insignificant effect on childlessness; and (f) education is positively associated with childlessness, with the effect of education increasing and reaching strikingly high levels for the most recent cohorts.     

Convergence on the two-child family norm in Australia

This paper examines childbearing patterns of ever-married women in Australia and establishes that during the process of fertility transition from high to low levels which largely began after 1971, significant changes occurred in the timing of the first birth after marriage, the length of the first and inter-birth intervals and the proportion of women progressing to have a first birth or births beyond the second. The analysis also confirms the predominance of the twochild family norm and shows the emergence of a converging trend on that family norm. The study applies the life tables technique to the marriage and birth history data collected in the Family Formation Survey conducted by the ABS in September 1986.     

Baby boomlet for older mothers?

In recent years, a number of celebrities have begun childbearing after age 35. The phenomena of older first-time mothers has received a great deal of attention in the popular press. Are these celebrities indicative of a national trend? Does the increase in fertility portend a reversal of the declines in fertility which have been occurring since the baby boom? The present paper uses central and cumulative birth rates for cohorts of American white women born between 1882 and 1953 to investigate childbearing between ages 35 and 50. While there has been a noticeable upsurge in first birth rates for cohorts in their mid to late 30s in recent years, overall central birth rates for women in their 30s are among the lowest on record, with cumulative birth rates at record low levels. A major reason for this is that these women are having relatively few third and higher order births. These cohorts will need to have a relatively high proportion of births in their older years of childbearing in order to reach replacement level. However, attaining replacement level is unlikely because such a high proportion of women have remained childless at ages 35–40 and a relatively low proportion are having three or more children.     

性别视角下的迁移历程研究——基于中国1930～1969年出生队列的分析

利用2014年中国健康与养老追踪调查生命历程数据,探究中国1930～1969年出生队列的迁移历程及其性别差异,运用事件史分析方法解释重要生命事件(教育、就业、婚姻、生育)对男性和女性迁移历程的影响。研究结果表明,不同出生年代人口的迁移历程呈现明显的队列差异和性别差异;与1940～1949年和1950～1959年出生队列相比,1930～1939年和1960～1969年出生队列在迁移高峰年龄(20～24岁)时的政策限制较少而终身累计迁移频率更高,性别差异也更显著;教育和非农就业转移会促进终身迁移机会,较早结婚和较多生育的作用则相反;非农就业转移对女性的多次迁移有更明显的促进作用,会缩小男女之间的迁移差距;结婚和生育会降低迁移概率,而离婚会增加迁移概率,这些事件对女性的影响更大。     

Premarital socioeconomic roles and the timing of family formation: A comparative study of five Asian societies

The impact of female socioeconomic activities on cumulative fertility is a product of a series of life cycle stages, including the initiation of marriage and the timing of subsequent births. In the present paper, the effects of premarital socioeconomic roles on the first stages of family formation—the timing of marriage and the interval between marriage and first birth—are analyzed. Modern socioeconomic roles, especially educational attainment, lead to a postponement of marriage, and thereby age at first birth. However, the same variables tend to have a counterbalancing effect by reducing the interval from marriage to the first birth.     

The temporal relationship of marriage,conception, and birth in Massachusetts

An investigation into the timing of first births in relationship to the date of marriage in Massachusetts confirmed the finding of previous national and local birth timing studies that first births likely to have been conceived before the marriage of their parents constitute a substantial proportion of all first births. The differential frequency of premaritally conceived births among various subgroups appeared to account for the variation noted in the overall timing patterns of first births after marriage. Data were gathered through linkage of certificates of birth of a sample of legitimate first children with the marriage record of their parents. Analysis of the marriage-first birth interval by maternal age and race, type of marriage ceremony, and occupation of the bride and groom were conducted and comparisons with previously published data were made. Separate consideration was given to the frequency and characteristics of those births likely to be premaritally conceived and those likely to have been conceived after the wedding.     

The negligible influence of premarital cohabitation on marital fertility in current danish cohorts, 1975

This paper studies the influence of premarital cohabitation on marital fertility by applying life table methods to data for cohorts of Danish women born in 1926–1955, collected in retrospective interviews made in 1975. For each five-year cohort, the data have been analyzed by duration of marriage or by duration since previous birth, for women who had no reported births before marriage. Our main empirical results are: (a) that women who married at age 15–19 had higher rates of marital first and second births than those married at ages 20–24, and (b) that premarital cohabitation had very little influence on births of these two first orders in our data.     

The Untold Story of 50 Years of Adolescent Fertility in West Africa: A Cohort Perspective on the Quantum,Timing, and Spacing of Adolescent Childbearing

Although recent studies examine overall fertility trends in West Africa, few using advanced demographic techniques focus on adolescents. This study explores long‐term patterns of adolescent childbearing in 12 West African countries using 51 Demographic and Health Surveys covering birth cohorts that span 54 years (1940–1994). We employ classic demographic measures as well as disaggregation by early‐ (10–14 years old), middle‐ (15–17), and late adolescence (18–19). Cohort‐based estimates of total adolescent births, parity progression ratios, and rapid repeat birth probabilities reveal little change over time. Most women begin childbearing in adolescence, the progression to additional adolescent births remains common, and the incidence of rapid repeat births is high. In recent cohorts, women exit adolescence with an average of between 0.4 (Ghana) to 1.3 (Niger) births. Contrary to common assumptions, it is women commencing motherhood in early‐ and middle‐, not later adolescence, who account for most West African adolescent fertility.     

The construction of the fertility model of variable parity from family planning practice]

Understanding the changing patterns of age specific fertility under the planning system is essential for building a fertility model which reflects birth control policy implementation in China. In building a Parity Variable Fertility Model, 4 basic elements are to be considered: 1) psychosocial, and physiological variables, 2) patterns of the total fertility rate and age-specific fertility rate, 3) socioeconomic development, and 4) distribution of parity-specific fertility. THe natural fertility of women is 17, calculated from a 309-years childbearing period, with 17% of non-susceptible time. In China, about 86% of natural fertility is suppressed by various factors. In this model, the following variables are included: 1) The first marriage ratio, which is the proportion of women in each age group which enters into a first marriage. The range and spread of this ratio is closely associated with the first birth. 2) The first birth ratio, which is the proportion of a marriage cohort to have a first birth each year. 3) the birth interval, which determines the distribution of second births. 4) Regulation coefficient B, which represents birth control regulations which approximately determine the number of second-parity or higher order births. The difference between the fertility level generated from the Parity Variable Fertility Model and reality depends on the implementation of birth control program, the assumptions on regulation coefficients, and changes in social and cultural factors. The model is easy to use, especially for areas where the marriage and fertility records of women of child-bearing are well kept.     

Individual and aggregate influences on the age at first birth

This study examines the role of both individual adolescent expectations of market and nonmarket income and aggregate influences on first birth timing for Blacks and Whites and for three birth cohorts of American women. Using two panels of the National Longitudinal surveys, results suggest that between-race differences in age at first birth result from differences in individual expectations about market and nonmarket income. Cohort differences in age at first birth result from relationship differences in both individual and aggregate influences, with aggregate influences differentially altering the role of individual expectations on first birth timing. These results suggest that employment policies that reduce poverty and increase wages would effectively delay childbearing. For Blacks, since early childbearing results from lower expectations about future economic success, similar fertility timing patterns between the races would result if Blacks had White employment and wage levels. Over time, these employment and wage policies will not only alter individual expectations about economic success but also will alter the impact of expectations on fertility timing.     

Coresidence With Husband’s Parents,Labor Supply,and Duration to First Birth

This article investigates the time to first birth, treating coresidence with husband’s parents and labor supply as endogenous and using representative data on Taiwanese married women born during 1933–1968. We use a full-information maximum likelihood estimator for a duration model with endogenous binary variables. Results controlling for endogeneity suggest that both coresidence and working are associated with a delay in childbearing, reversing the effect of coresidence on the timing of first birth but not that of working. Women in earlier cohorts tend to choose coresidency and not working, and an increasing number of women from later cohorts choose to do both or to work only.     

Sibling models of socioeconomic effects on the timing of first premarital birth

Data on 1,090 pairs ofsisters from the National Longitudinal Survey of Youth are used to estimate the effects of observed individual-level factors, common family-level variables, and shared unobserved family-level traits on the timing of premarital births. Results show a moderate correlated risk of premarital childbearing among siblings after controlling for the effects of measured covariates. The effect of older sisters’ out-of-wedlock childbearing on the timing of younger sisters’ premarital birth is overestimated when shared unmeasured family-level traits are ignored. Public policy measures designed to reduce premarital births have a smaller multiplier effect via reduced younger sisters’ premarital births because unmeasured family-level factors are less amenable to policy measures. However, because the older-sibling effect is large when other sources of variability in premarital birth timing are controlled, interventions may be effective in reducing premarital births among young women in high-risk families.     

Birth spacing and fertility limitation: a behavioral analysis of a nineteenth century frontier population

Our analysis of changing birth interval distributions over the course of a fertility transition from natural to controlled fertility has examined three closely related propositions. First, within both natural fertility populations (identified at the aggregate level) and cohorts following the onset of fertility limitation, we hypothesized that substantial groups of women with long birth intervals across the individually specified childbearing careers could be identified. That is, even during periods when fertility behavior at the aggregate level is consistent with a natural fertility regime, birth intervals at all parities are inversely related to completed family size. Our tabular analysis enables us to conclude that birth spacing patterns are parity dependent; there is stability in CEB-parity specific mean and birth interval variance over the entire transition. Our evidence does not suggest that the early group of women limiting and spacing births was marked by infecundity. Secondly, the transition appears to be associated with an increasingly larger proportion of women shifting to the same spacing schedules associated with smaller families in earlier cohorts. Thirdly, variations in birth spacing by age of marriage indicate that changes in birth intervals over time are at least indirectly associated with age of marriage, indicating an additional compositional effect. The evidence we have presented on spacing behavior does not negate the argument that parity-dependent stopping behavior was a powerful factor in the fertility transition. Our data also provide evidence of attempts to truncate childbearing. Specifically, the smaller the completed family size, the longer the ultimate birth interval; and ultimate birth intervals increase across cohorts controlling CEB and parity. But spacing appears to represent an additional strategy of fertility limitation. Thus, it may be necessary to distinguish spacing and stopping behavior if one wishes to clarify behavioral patterns within a population (Edlefsen, 1981; Friedlander et al., 1980; Rodriguez and Hobcraft, 1980). Because fertility transition theories imply increased attempts to limit family sizes, it is important to examine differential behavior within subgroups achieving different family sizes. It is this level of analysis which we have attempted to achieve in utilizing parity-specific birth intervals controlled by children ever born.(ABSTRACT TRUNCATED AT 400 WORDS)     

Fertility Following an Unintended First Birth

Research on unintended fertility tends to focus on births as isolated events. This article expands previous research by examining the relationship between early unintended childbearing and subsequent fertility dynamics in the United States. Data from the 2002 National Survey of Family Growth show that 27.5% of mothers report an unintended first birth. We use event history methods to show that these women are significantly more likely than women with an intended first birth to have an unintended second birth than to have either no second birth or an intended second birth, net of sociodemographic characteristics. An unintended first birth also increases the risk of having an unintended third birth relative to no birth or an intended birth, independent of the intendedness of the second birth. We conclude that early unintended fertility is a strong signal of high risk for subsequent unintended fertility.