Father Absence and Accelerated Reproductive Development in Non-Hispanic White Women in the United States

Girls who experience father absence in childhood also experience accelerated reproductive development in comparison with peers with present fathers. One hypothesis advanced to explain this empirical pattern is genetic confounding, wherein gene-environment correlation (rGE) causes a spurious relationship between father absence and reproductive timing. We test this hypothesis by constructing polygenic scores for age at menarche and first birth using recently available genome-wide association study results and molecular genetic data on a sample of non-Hispanic white females from the National Longitudinal Study of Adolescent to Adult Health. We find that young women’s accelerated menarche polygenic scores are unrelated to their exposure to father absence. In contrast, polygenic scores for earlier age at first birth tend to be higher in young women raised in homes with absent fathers. Nevertheless, father absence and the polygenic scores independently and additively predict reproductive timing. We find no evidence in support of the rGE hypothesis for accelerated menarche and only limited evidence in support of the rGE hypothesis for earlier age at first birth.     

Sexual violence at first intercourse against women in Moshi, northern Tanzania: prevalence, risk factors, and consequences

To explore the relationship between sexual violence at first intercourse and later sexually transmitted infections (STIs) in Moshi, Tanzania, we analysed data from a representative household survey that comprised face-to-face interviews with 1,835 women and tests for six STIs on biological samples from 1,235 of these women. Overall, 10.9 per cent report forced first intercourse and 15.3 per cent report unwanted first intercourse. Unadjusted analysis shows a relationship between forced first intercourse and STIs (OR: 1.72, 95 per cent CI: 1.19-2.51). Life-course variables mediate this relationship. Significant predictors of having an STI include older age, more sexual partners, and a partner who has children with other women. Coerced first intercourse appears to be associated with changes in the life course of women and with a heightened risk of contracting an STI.     

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.     

Premarital first births: The influence of the timing of sexual onset versus post-onset risks in the United States

Motivated by long-standing debates between abstinence proponents and sceptics, we examine how socio-economic factors influence premarital first births via: (i) age at first sexual intercourse and (ii) the risk of a premarital first birth following the onset of sexual activity. Factors associated with an earlier age at first intercourse will imply more premarital first births owing to increased exposure to risk, but many of these same factors will also be associated with higher risks of a premarital first birth following onset. Our analyses confirm previous findings that women from disadvantaged backgrounds are younger at first intercourse and have higher premarital first-birth risks than women from more advantaged backgrounds. However, differences in onset timing have a strikingly smaller influence on premarital first-birth probabilities than do differences in post-onset risks. Our findings thus suggest that premarital first births result primarily from differences in post-onset risk behaviours as opposed to differences in onset timing.     

Contraceptive use at first intercourse among Jewish women in Israel, 1962–1988

Using data from the 1987–1988 Study of Fertility and Family Formation,this study examines the family planning practices of Jewish Israeli womenwho first had intercourse between 1962 and 1988. The overwhelming majorityof women reported using no contraception at first intercourse, and among those who did practice birth control approximately half relied on modern techniques. While the likelihood that Israeli women used contraception at first sex changed little between 1962 and 1988, there has been a marked shift towards the adoption of efficient methods of birth control. Moreover, factors which promote female empowerment, including education and military service, have been positively associated with contraceptive use at first intercourse. Among those women who practiced contraception at first intercourse, those from Africa and Asia have been especially likely to make use of inefficient methods such as withdrawal.     

Motherhood status and union formation in Moshi, Tanzania 2002-2003

Age at first union is increasing throughout much of sub-Saharan Africa at the same time that not all couples are waiting for marriage before their first sexual intercourse. We assessed the effect of a premarital first birth on entrance into a first union in an urban area in East Africa -- Moshi, Tanzania. The data come from the Moshi Infertility Survey of 2002-2003. Women who spent less than a year in single motherhood were significantly more likely than childless women to enter into a first union, although the magnitude of this relationship was weaker for more recent cohorts. Women who had been single mothers for 5 or more years (about two-thirds of women with a premarital birth) were significantly less likely than women without children to enter into a first union.     

Motherhood status and union formation in Moshi,Tanzania 2002–2003

Age at first union is increasing throughout much of sub-Saharan Africa at the same time that not all couples are waiting for marriage before their first sexual intercourse. We assessed the effect of a premarital first birth on entrance into a first union in an urban area in East Africa—Moshi, Tanzania. The data come from the Moshi Infertility Survey of 2002–2003. Women who spent less than a year in single motherhood were significantly more likely than childless women to enter into a first union, although the magnitude of this relationship was weaker for more recent cohorts. Women who had been single mothers for 5 or more years (about two-thirds of women with a premarital birth) were significantly less likely than women without children to enter into a first union.     

The contribution of HIV to fertility decline in rural Zimbabwe, 1985-2000

HIV-related sub-fertility has been reported for those populations in sub-Saharan Africa in which contraceptive use is low. We use data from a retrospective survey in rural Zimbabwe and multivariate logistic regression models to show that recent birth rates and current pregnancy rates are also lower among HIV-positive women than among HIV-negative women in those African populations where contraceptive use is high. The fertility reduction is smaller than where contraceptive use is low because age at first sexual intercourse is later and birth rates at older ages are already low. Nevertheless, total fertility is approximately 8.5 per cent lower and HIV-associated sub-fertility may account for as much as one-quarter of fertility decline in Zimbabwe since the late 1980s. Mechanisms for HIV-associated sub-fertility in rural Zimbabwe include more frequent widowhood and divorce, reduced coital frequency, increased amenorrhoea, and possibly, pelvic inflammatory disease. Miscarriage appears to be a less important factor than elsewhere possibly because syphilis is rare.     

Birth month,school graduation,and the timing of births and marriages

We investigated the timing of fertility and marriage in Sweden using exogenous variation in the age at school graduation that results from differences in birth month. Our analysis found that the difference of 11 months in the age at leaving school between women who were born in two consecutive months, December and January, implies a delay in the age at first birth of 4.9 months. This effect of delayed graduation also persists for the timing of second births and first marriages, but it does not affect completed fertility or the overall probability of marriage before age 45. These results suggest the existence of a relatively rigid sequencing of demographic events in early adulthood, and the age at graduation from school emerges as an important factor in determining the timing--but not the quantum--of familyformation. In addition, these effects point to a potentially important influence of social age, defined by an individual's school cohort, instead of biological age. The relevance of social age is likely due to social interactions and peer-group influences exerted by individuals who are in the same school cohort but are not necessarily of the same age.     

Trends in the age at reproductive transitions in the developing world: The role of education

Girls’ school participation has expanded considerably in the developing world over the last few decades, a phenomenon expected to have substantial consequences for reproductive behaviour. Using Demographic and Health Survey data from 43 countries, this paper examines trends and differentials in the mean ages at three critical life-cycle events for young women: first sexual intercourse, first marriage, and first birth. We measure the extent to which trends in the timing of these events are driven either by the changing educational composition of populations or by changes in behaviour within education groups. Mean ages have risen over time in all regions for all three events, except age at first sex in Latin America and the Caribbean. Results from a decomposition exercise indicate that increases in educational attainment, rather than trends within education groups, are primarily responsible for the overall trends. Possible explanations for these findings are discussed.     

Exploring First Sexual Intercourse,Sexual Orientation,and Sexual Health in Men

In this study the characteristics of the sexual debut of men who have sex with men (MSM) and men who have sex with women (MSW) age 35 or younger (N = 1,201) were compared with one another. We investigated whether these characteristics were associated with sexual health and behavior, and to what extent. Compared to MSW, MSM tended to be older when they had their first sexual intercourse; their first sex partner was older, they felt less ready, and they experienced more pain. We also found that they reported a higher number of lifetime sexual partners and less condom use compared to MSW. Similarities were also ascertained, such as the fact that individuals from both groups do not differ significantly regarding how they experienced their first sexual intercourse emotionally. Many differences between these groups should not always be seen as problematic, whereas others still indicate a need for targeted interventions.     

The seasonality of conception

Individual data on menstrual cycles of noncontracepting women living in Western countries were used in order to verify whether the biological seasonality of conception persists after sexual behavior is controlled for. Episodes of intercourse were recorded daily, and the time of ovulation was detected by a marker We find that the seasonality of conception changes with woman's age and frequency of episodes of sexual intercourse. In particular; for women aged 27-31 having only one act of intercourse during the six most fertile days of the menstrual cycle, the seasonality of fecundability is stronger In this age group in the Northern Hemisphere, if seasonality of acts of sexual intercourse is controlled, the monthly distribution of probability of conception is bimodal, with two maxima (September and January) and two minima (December and March). When unobserved characteristics of the couples are considered, this seasonal pattern of conception persists.     

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.     

Reproductive impairments in the united states, 1965–1982

The first national estimates of current fecundity status of women of all marital statuses indicate that, in 1982, about 5.1 million women were unable to have a future birth but would have liked to. About 2.7 million had difficulty bearing children, and the other 2.4 million were surgically sterile for noncontraceptive reasons. Since 1965, infertility was unchanged overall and in most age groups, but increased among wives aged 20–24. This paper explores a number of methodological and substantive questions related to reproductive impairments, such as the frequency of intercourse, the duration of infertility, and the possible causes of trends.     

Schooling,marriage, and age at first birth in Madagascar

The low school attainment, early marriage, and low age at first birth of females are major policy concerns in less developed countries. This study jointly estimated the determinants of educational attainment, marriage age, and age at first birth among females aged 12–25 in Madagascar, explicitly accounting for the endogeneities that arose from modelling these related outcomes simultaneously. An additional year of schooling results in a delay to marriage of 1.5?years and marrying 1?year later delays age at first birth by 0.5?years. Parents’ education and wealth also have important effects on schooling, marriage, and age at first birth, with a woman's first birth being delayed by 0.75?years if her mother had 4 additional years of schooling. Overall, our results provide rigorous evidence for the critical role of education—both individual women's own and that of their parents—in delaying the marriage and fertility of young women.     

Family transitions in Young Adulthood

Using the first (1995) and third (2001-2002) waves of the Add Health survey, we examine women 's family transitions up to age 24. Only a third of all women marry, and a fifth of those marriages dissolve before age 24. Three out of eight women have afirst birth, with a substantial majority of those births outside of marriage: 66% for whites, 96% for blacks, and 72% for Mexican Americans. Cohabitation is the predominant union form; 59% of women cohabit at least once by age 24. Most cohabitations are short lived, with approximately one in five resulting in a marriage. We summarize the family and relationship experience of women up to age 24 in terms offour categories, each accounting for roughly a quarter of all women. Category 1 has the women who remain single nonparents. Category 2 has the early marriers, women whose marriage is not preceded by a first birth. Category 3 has those who become single parents. Category 4 has the women who cohabit at least once, but who do not marry or have a birth by age 24. The strictly ordered transitions of the 1950s are long gone and have been replaced by a variety of paths to adulthood.     

Dynamics of contraceptive use and breastfeeding during the post-partum period in Peru and Indonesia

This paper examines the interaction between contraceptive use and breastfeeding in relation to resumption of intercourse and duration of amenorrhea post-partum. We used data from the month-by-month calendar of reproductive events from Demographic and Health Surveys (DHS) in Peru and Indonesia. The analyses show that breastfeeding women were less likely than non-breastfeeding women to have resumed sexual intercourse in the early months post-partum in both countries. In Peru, but not in Indonesia, breastfeeding women had a significantly lower odds than non-breastfeeding women of adopting contraception. Although the likelihood of contraceptive adoption was highest in the month women resumed menstruation in both countries, about ten per cent of subsequent pregnancies occurred to women before they resumed menses. These results emphasize the importance of integrating breastfeeding counselling and family planning services in programmes serving post-partum women, as a means of enabling those who wish to space their next birth to avoid exposure to the risk of a pregnancy that may precede the return of menses.     

A cohort analysis of the timing of first birth and fertility in Ghana

This paper examines the nature of the inverse association between age at first birth and fertility across successive generations of Ghanaian women. Within the context of enhanced non-marital opportunities for contemporary women and declining fertility, we develop a rationale for and test the hypothesis that in a medium fertility environment as currently found in Ghana, the effect of age at first birth on fertility becomes more important than ever before. Five birth cohorts were identified (1938–1944; 1945–1949;1950–1954; 1955–1959; 1960–1964)from a merged file of the 1988, 1993 and 1998 Ghana Demographic and Health Surveys. The analyses were restricted to women over 35 years old at the time of the surveys, which allowed us to use current parity as a reasonable proxy for completed fertility. Preliminary results suggest that women who had first births early tend to have a higher number of births than those whose first births occur late, regardless of birth cohort. In multivariate analyses, the effect of age at first birth as a determinant of fertility was found to be more substantial among later cohorts. The implications of the findings are discussed.     

Regardless of where they give birth,women living in non-metropolitan areas are less likely to have an epidural than their metropolitan counterparts

QuestionCan differences in Australian birth intervention rates be explained by women's residence at the time of childbearing?.MethodsData were collected prospectively via surveys in 1996, 2000, 2003, 2006 and 2009 from women, born between 1973 and 1978, of the Australian Longitudinal Study on Women's Health. Analysis included data from 5886 women who had given birth to their first child between 1994 and 2009. Outcome measures were self-report of birth interventions: pharmacological pain relief (epidural and spinal block analgesia, inhalational analgesia and intramuscular injections), surgical births (an elective or emergency caesarean section) and instrumental births (forceps and ventouse).FindingsPrimiparous women residing in non-metropolitan areas of Australia experienced fewer birth interventions than women residing in metropolitan areas: 43% versus 56% received epidural analgesia; 8% versus 11% had elective caesarean sections; and 16% versus 18% had emergency caesarean sections. Differences in maternal age and private health insurance status at first birth accounted for differences in surgical birth rates but did not fully explain differences in epidural analgesia.ConclusionNon-metropolitan women had fewer birth interventions, particularly epidural analgesia, than metropolitan women. Differences in maternal age and private health insurance do not fully explain the differences in epidural analgesia rates, suggesting care provided to labouring women may differ by area of residence. The difference in epidural analgesia rates may be due to lack of choice in maternity services, however it could also be due to differing expectations leading to differences in birth interventions for primiparous women living in metropolitan and non-metropolitan areas.