All about babies
Nathan Berg & Teresa Nelson
Population Research and Policy Review, December 2016, Pages 757–789
Abstract:
Administrative data from multiple sources are combined to measure pregnancy (excluding those ending in abortion or miscarriage) and high school dropout in a cohort of girls who were 9th graders in the 1994–1995 academic year. Rates of pregnancy (as identified in the data) and dropout are substantially higher among Hispanic high school students than among African-Americans or non-Hispanic whites. Previous studies of teen pregnancy and dropout typically focus on pregnancy rates conditional on dropout status, or dropout rates conditional on fertility. This paper presents estimates of pregnancy and dropout as a joint-dependent variable. Estimates of their joint probability distribution conditional on individual, family, neighborhood, and high school characteristics are reported. The estimates use longitudinal administrative data collected as annual censuses of all public school students in Texas with individual-level ids. Neighborhood characteristics (from the US Census data geographically linked to Texas high schools) have large effects on pregnancy and dropout. Immigrant Hispanic girls’ pregnancy rates are significantly lower than native-born Hispanic girls’ pregnancy rates. Above-normal-age status in the 9th grade is among the strongest predictors of pregnancy and dropout in later years. Ethnic differences in age distributions within grade level appear to explain a large share of ethnic differences in pregnancy and dropout rates.
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Anne Davis, Sarah Horvath & Paula Castaño
American Journal of Obstetrics and Gynecology, forthcoming
Study Design: We conducted a retrospective case series of all women undergoing surgical abortion for fetal aneuploidy or structural abnormalities up to 24 weeks gestation from 2004 through 2014 in a hospital operating room setting at a single, urban medical center. We excluded labor induction abortions (<1% of abortions at our medical center) and suction aspirations performed in the office practice. We performed suction aspiration up to 14 weeks and dilation and evacuation after that gestational age. We describe the median gestational age at abortion by fetal indication and year.
Results: For women undergoing abortion for fetal aneuploidy (n = 392), the median gestational age at time of abortion decreased from 19.0 weeks (interquartile range 18.0-21.0) in 2004 to 14.0 weeks (interquartile range 13.0-17.0) in 2014 (Kruskal Wallis P < .0001). For women undergoing abortion for fetal structural abnormalities (n = 586), the median gestational age was ≥ 20 weeks for each year during the study interval (P = .1). As gestational age decreased in the fetal aneuploidy group, fewer women underwent dilation and evacuation and more became eligible for suction aspiration (<14 weeks). In 2004, >90% of women underwent dilation and evacuation for either indication. By 2014, 31% of women with fetal aneuploidy were eligible for suction aspiration compared to 11% of those with structural anomalies.
Conclusion: Gestational age at the time of abortion for fetal aneuploidy decreased substantially from 2004 to 2014; earlier abortion is safer for women. In contrast, women seeking abortion for fetal structural abnormalities did not experience a change in timing. Legislation restricting gestational age at the time of abortion could disproportionately affect women with fetal structural abnormalities.
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State Abortion Policy and Unintended Birth Rates in the United States
Marshall Medoff
Social Indicators Research, November 2016, Pages 589–600
Abstract:
Restrictive state abortion laws make it more difficult and costly for women to obtain an abortion. The fundamental law of demand posits that an increase in the cost of an abortion should cause the number of abortions to decrease. This suggests that restrictive state abortion laws should cause women with unintended pregnancies to have fewer abortions and concomitantly more unintended births. This paper investigates the impact four restrictive state abortion laws — No Medicaid Funding, Parental Involvement, Mandatory Counseling and Waiting Periods — have on the unintended birth rates of the 50 US states for the year 2006. Using a variety of methodologies, the empirical results show that, contrary to the theoretical prediction, these four antiabortion laws do not have a significant positive effect on unintended birth rates.
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Black-White Differences in Sex and Contraceptive Use Among Young Women
Yasamin Kusunoki et al.
Demography, October 2016, Pages 1399–1428
Abstract:
This study examines black-white and other sociodemographic differences in young women’s sexual and contraceptive behaviors, using new longitudinal data from a weekly journal-based study of 1,003 18- to 19-year-old women spanning 2.5 years. We investigate hypotheses about dynamic processes in these behaviors during early adulthood in order to shed light on persisting racial differences in rates of unintended pregnancies in the United States. We find that net of other sociodemographic characteristics and adolescent experiences with sex and pregnancy, black women spent less time in relationships and had sex less frequently in their relationships than white women, but did not differ in the number of relationships they formed or in their frequency or consistency of contraceptive use within relationships. Black women were more likely to use less effective methods for pregnancy prevention (e.g., condoms) than white women, who tended to use more effective methods (e.g., oral contraceptives). And although the most effective method for pregnancy prevention — long-acting reversible contraception (LARC) — was used more often by black women than white women, LARC use was low in both groups. In addition, black women did not differ from white women in their number of discontinuations or different methods used and had fewer contraceptive method switches. Further, we find that net of race and adolescent experiences with sex and pregnancy, women from more-disadvantaged backgrounds had fewer and longer (and thus potentially more serious) relationships, used contraception less frequently (but not less consistently), and used less effective methods (condoms) than women from more-advantaged backgrounds.
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Michael Woodley of Menie & Satoshi Kanazawa
Personality and Individual Differences, forthcoming
Abstract:
The effect of paternal age on offspring attractiveness has recently been investigated. Negative effects are predicted as paternal age is a strong proxy for the numbers of common de novo mutations found in the genomes of offspring. As an indicator of underlying genetic quality or fitness, offspring attractiveness should decrease as paternal age increases, evidencing the fitness-reducing effects of these mutations. Thus far results are mixed, with one study finding the predicted effect, and a second smaller study finding the opposite. Here the effect is investigated using two large and representative datasets (Add Health and NCDS), both of which contain data on physical attractiveness and paternal age. The effect is present in both datasets, even after controlling for maternal age at subject's birth, age of offspring, sex, race, parental and offspring (in the case of Add Health) socio-economic characteristics, parental age at first marriage (in the case of Add Health) and birth order. The apparent robustness of the effect to different operationalizations of attractiveness suggests high generalizability, however the results must be interpreted with caution, as controls for parental levels of attractiveness were indirect only in the present study.
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Pensions and fertility: Back to the roots
Robert Fenge & Beatrice Scheubel
Journal of Population Economics, January 2017, Pages 93–139
Abstract:
Fertility has long been declining in industrialised countries and the existence of public pension systems is considered as one of the causes. This paper provides detailed evidence on the mechanism by which a public pension system depresses fertility, based on historical data. Our theoretical framework highlights that the effect of a public pension system on fertility is ex ante ambiguous while its size is determined by the internal rate of return of the pension system. We identify an overall negative effect of the introduction of pension insurance on fertility using regional variation across 23 provinces of Imperial Germany in key variables of Bismarck’s pension system, which was introduced in Imperial Germany in 1891. The negative effect on fertility is robust to controlling for the traditional determinants of the first demographic transition as well as to other policy changes.
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Abortion, Property, and Liberty
William Simkulet
Journal of Ethics, December 2016, Pages 373–383
Abstract:
In “Abortion and Ownership” John Martin Fischer argues that in Judith Jarvis Thomson’s violinist case you have a moral obligation not to unplug yourself from the violinist. Fischer comes to this conclusion by comparing the case with Joel Feinberg’s cabin case, in which he contends a stranger is justified in using your cabin to stay alive. I argue that the relevant difference between these cases is that while the stranger’s right to life trumps your right to property in the cabin case, the violinist’s right to life does not trump your right to liberty in the violinist case.
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Bingjing Li & Hongliang Zhang
Journal of Comparative Economics, forthcoming
Abstract:
Scholarly evidence on the quantity-quality trade-off is mixed in part because of the identification challenge due to endogenous family size. This paper provides new evidence of the causal effect of child quantity on child quality by exploiting regional differences in the enforcement intensity of China’s one-child policy (OCP) as an exogenous source of variation in family size. Using the percentage of current mothers of primary childbearing age who gave a higher order birth in 1981, we construct a quantitative indicator of the extent of local violation of the OCP, referred to as the excess fertility rate (EFR). We then use regional differences in EFRs, net differences in pre-existing fertility preferences and socio-economic characteristics, to proxy for regional differences in OCP enforcement intensity. Using micro data from the Chinese Population Censuses, we find that prefectures with stricter enforcement of the OCP have experienced larger declines in family size and also greater improvements in children’s education. Despite the evident trade-off between family size and child quality in China, our quantitative estimates suggest that China’s OCP makes only a modest contribution to the development of its human capital.
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The effects of teenage childbearing on long-term health in the US: A twin-fixed-effects approach
Pınar Mine Güneş
Review of Economics of the Household, December 2016, Pages 891–920
Abstract:
This paper explores the effect of teenage childbearing on long-term health outcomes and behaviors of mothers using the Midlife Development in the US dataset. Within-family estimations, using samples of siblings, and twin pairs, are employed to overcome the bias generated by unobserved family background and genetic traits. The results suggest no significant effects on health outcomes, and modest effects on health behaviors, including exercise and preventive care. However, accounting for life-cycle effects demonstrates that teenage childbearing has significant effects on both health outcomes and behaviors early in life, but very few significant effects later in life. Moreover, teenage childbearing has a particularly acute effect among minorities. Finally, this paper provides evidence that the effects operate through reduced income and labor force participation, and matching with a lower “quality” spouse.
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No relationship between abortion numbers and maternal cognitive ability
Michael Woodley of Menie, Justus Sänger & Gerhard Meisenberg
Personality and Individual Differences, January 2017, Pages 489–492
Abstract:
The relationship between maternal cognitive ability (as indicated by g and highest attained educational level) and self-reported numbers of abortions at near-completed fertility is investigated in two, population representative samples of the US: (i) a sample of 1386 women, sourced from NLSY’79 (aged 39–47), and (ii) a sample 842 women (aged 38–45), sourced from NSFG’11–13. No linear relationships between either of the cognitive ability measures and abortion numbers were found, nor were quadratic effects present in these data. Income had an independent negative effect on abortion numbers in the NSFG’11–13 sample, whereas age was a positive independent predictor in the NLSY’79 sample. The essentially zero-magnitude association between maternal cognitive ability and abortion numbers may have resulted from the wide scale destigmatization of elective abortion as a birth-control technique in the US following the 1973 US Supreme Court ruling in Roe v. Wade. Despite this, self-reported abortion numbers data typically underrepresent the true numbers of abortions hence these findings must be considered tentative especially if underreporting is unsystematic with respect to any of the predictors.
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Embryo quality: The missing link between pregnancy sickness and pregnancy outcome
Scott Forbes
Evolution and Human Behavior, forthcoming
Abstract:
Pregnancy sickness is widespread yet its etiology is poorly understood. It is almost certainly endocrine in origin and most likely a product of placental hormones, with human chorionic gonadotropin being the strongest candidate. It has long been known that greater levels of nausea and vomiting during pregnancy are associated with a lower incidence of spontaneous abortion, yet the causal mechanisms remain unclear. One current popular explanation is that nausea and vomiting during pregnancy is fetoprotective, inducing aversions to foods, especially meat, dairy and seafoods, which may carry toxins, pathogens or mutagens. However, most spontaneous abortions arise from genetic or epigenetic defects that are present at or near conception. Moreover, measurements of human chorionic gonadotropin (hCG) at the time of implantation, particularly its hyperglycosylated isoform, accurately predict subsequent spontaneous abortion. Thus the developmental fate of most embryos is fixed before the onset of the symptoms of pregnancy sickness. An alternative explanation for the link between pregnancy sickness and spontaneous abortion is the embryo quality hypothesis: high quality embryos are both more likely to produce the biochemical antecedents of pregnancy sickness and avoid spontaneous abortion. Recent work has shown that the link between pregnancy sickness and spontaneous abortion grows stronger with maternal age, dramatically so in mothers 35 or older. This reflects the parallel rise in the incidence of autosomal aneuploidies with maternal age. The link between pregnancy sickness and spontaneous abortion exists not because nausea and vomiting during pregnancy is fetoprotective, but because nausea and vomiting is an index of a high quality embryo. Pregnancy sickness is not adaptive pers se, but the result of an antagonistic pleiotropy over thyroid function, where embryos use hCG to modulate maternal thyroid hormone production during gestation. Embryos benefit from the thyroid hormone production that is key to neurodevelopment, but produce maternal nausea and vomiting as a by-product. Pregnancy sickness, however, may still serve to protect embryo quality but by a different mechanism that posited under the MEPH. Embryo quality is protected by calibrating the dietary intake of a micronutrient – iodine – critical to neuromotor development. For most humans over most of our evolutionary history, iodine has been in short supply, and iodine deficiency is still the most common source of cognitive impairment across the globe. Thus it is of interest that the foods aversions most commonly associated with pregnancy sickness, to meat, dairy and seafoods, are also the chief dietary sources of iodine. There is a further intriguing property about iodine: both too little and too much during early pregnancy is damaging to embryo brain development. Given that pregnancy sickness is closely linked to iodine intake and thyroid function (hypothyroidism is associated with lower levels of nausea and vomiting, hyperthyroidism with more), an obvious interpretation emerges. The previously described link between diet and pregnancy sickness – pregnancy sickness is less likely when plants and particularly corn / maize are the sole food staples – arises not because plant food staples are safe, as previously suggested, but because these foods are iodine poor and may, in addition, be goitrogenic. Pregnancy sickness, which reduces the dietary intake of iodine, is clearly maladaptive under conditions of iodine deficiency and hypothyroidism. Conversely, higher levels of pregnancy sickness induced by hyperthyroidism may protect embryos from the inimical effects of excessive dietary iodine during early gestation by reducing the intake of iodine rich foods.
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Malaria Ecology, Child Mortality & Fertility
Gordon McCord, Dalton Conley & Jeffrey Sachs
Economics & Human Biology, February 2017, Pages 1–17
Abstract:
The broad determinants of fertility are thought to be reasonably well identified by demographers, though the detailed quantitative drivers of fertility levels and changes are less well understood. This paper uses a novel ecological index of malaria transmission to study the effect of child mortality on fertility. We find that temporal variation in the ecology of the disease is well-correlated to mortality, and pernicious malaria conditions lead to higher fertility rates. We then argue that most of this effect occurs through child mortality, and estimate the effect of child mortality changes on fertility. Our findings add to the literature on disease and fertility, and contribute to the suggestive evidence that child mortality reductions have a causal effect on fertility changes.