Bearing Risk
Melissa Eccleston
Harvard Working Paper, November 2011
Abstract:
Exposure to maternal psychological stress in utero may have substantial negative effects on physical and mental health and cognitive ability. This paper estimates the causal effect of exposure to the stress of the September 11, 2001 terrorist attacks on the cohort in utero that day using birth data from the National Vital Statistics System and New York City public school records. The analysis finds that cohorts exposed during the first or second trimester in New York City weighed 12-14 grams less and had gestation lengths 1-1.5 days shorter on average. Male and female newborns were affected similarly. Births in the suburban counties surrounding the City and in the rest of the United States were not affected. Initial educational attainment in New York City also suffered: at the age of six, boys were 7-9% more likely to be in special education and 15-18% more likely to be in kindergarten rather than first grade, with no effect on girls. The analysis accounts for alternative causal channels, namely air pollution and economic recession. Effects estimated outside the area of air pollution are similar to estimates within it. Outcomes for a cohort exposed in utero to a period of high unemployment following 9/11, but not to the terrorist attacks themselves, are not adversely impacted. The results suggest that psychological stress is an important channel through which adverse conditions experienced by pregnant women negatively impact the early life outcomes of in utero cohorts.
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Ryan Brown
Duke University Working Paper, April 2012
Abstract:
A medical literature that provides biological pathways from maternal stress to adverse birth outcomes, coupled with a growing consensus that birth characteristics are predictive of later life wellbeing, suggest that events that cause psychological trauma during pregnancy may have dire consequences for the next generation. Due to the unexpected nature of the terrorist attacks of September 11th, 2001 a random cohort of in utero children where exogenously insulted by increased maternal psychological distress. The goal of this study is to rigorously examine the casual effect of acute maternal stress on birth outcomes. To explore this question, it is imperative to avoid two identification pitfalls common in natural experiment studies of this topic: non-stress related negative externalities and post-event endogenous fertility selection. With these issues in mind, this analysis excludes those individuals most at risk of health and resource shocks unrelated to stress, New York City and Washington D.C. residents, and does not rely on the endogenously selected post-event birth cohorts. Results suggest that the children exposed while in utero were born significantly smaller and early than previous cohorts. Additionally, intrauterine growth is specifically restricted by first trimester exposure to stress, while gestational age is most reduced by increased maternal psychological distress in mid pregnancy. Intriguingly, the magnitudes of the effects are quite small, suggesting that the human gestational process is mostly resilient to acute insults of psychological anxiety.
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Weathering the Storm: Hurricanes and Birth Outcomes
Janet Currie & Maya Rossin-Slater
NBER Working Paper, May 2012
Abstract:
A growing literature suggests that stressful events in pregnancy can have negative effects on birth outcomes. Some of the estimates in this literature may be affected by small samples, omitted variables, endogenous mobility in response to disasters, and errors in the measurement of gestation, as well as by a mechanical correlation between longer gestation and the probability of having been exposed. We use millions of individual birth records to examine the effects of exposure to hurricanes during pregnancy. The data allow us to measure outcomes precisely and to follow the same mother over time; we also suggest estimation methods that correct for omitted unobserved fixed characteristics of the mother, endogenous moving in response to storms, and the above mentioned correlation between gestation length and exposure. We find that exposure to a hurricane during pregnancy increases the probability of complications of labor and delivery, and of abnormal conditions of the newborn such as being on a ventilator more than 30 minutes and meconium aspiration syndrome. Although we do not directly measure stress, our results are supportive of the idea that stressful events in pregnancy can damage the health of the fetus. However our results suggest that the effects may be subtle and not readily apparent in terms of widely-used metrics such as birth weight and gestation.
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Prenatal growth in humans and postnatal brain maturation into late adolescence
Armin Raznahan et al.
Proceedings of the National Academy of Sciences, forthcoming
Abstract:
Prenatal life encompasses a critical phase of human brain development, but neurodevelopmental consequences of normative differences in prenatal growth among full-term pregnancies remain largely uncharted. Here, we combine the power of a within-monozygotic twin study design with longitudinal neuroimaging methods that parse dissociable components of structural brain development between ages 3 and 30 y, to show that subtle variations of the in utero environment, as indexed by mild birth weight (BW) variation within monozygotic pairs, are accompanied by statistically significant (i) differences in postnatal intelligence quotient (IQ) and (ii) alterations of brain anatomy that persist at least into late adolescence. Greater BW within the normal range confers a sustained and generalized increase in brain volume, which in the cortical sheet, is specifically driven by altered surface area rather than cortical thickness. Surface area is maximally sensitive to BW variation within cortical regions implicated in the biology of several mental disorders, the risk for which is modified by normative BW variation. We complement this near-experimental test of prenatal environmental influences on human brain development by replicating anatomical findings in dizygotic twins and unrelated singletons. Thus, using over 1,000 brain scans, across three independent samples, we link subtle differences in prenatal growth, within ranges seen among the majority of human pregnancies, to protracted surface area alterations, that preferentially impact later-maturing associative cortices important for higher cognition. By mapping the sensitivity of postnatal human brain development to prenatal influences, our findings underline the potency of in utero life in shaping postnatal outcomes of neuroscientific and public health importance.
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Opting for families: Recent trends in the fertility of highly educated women
Qingyan Shang & Bruce Weinberg
Journal of Population Economics, forthcoming
Abstract:
After declining for many years, there are indications that fertility may be increasing among highly educated women. This paper provides a comprehensive study of recent trends in the fertility of college-graduate women. In contrast to most existing work, we find that college graduate women are indeed opting for families. Data from the Current Population Surveys and Vital Statistics Birth Data both show that fertility increases among college graduate women, especially at older ages since the mid- to late 1990s. There are also increases in fertility among less-educated women, but these are concentrated at younger ages.
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Birth Rates and the Vietnam Draft
Marianne Bitler & Lucie Schmidt
American Economic Review, May 2012, Pages 566-569
Abstract:
The Vietnam conflict was the defining event for a generation, with nearly 8 million Americans serving in the armed forces. A large literature in economics has focused on effects of Vietnam-Era service post-war, while little research looks at contemporaneous effects of the mobilization, despite the potential for this mobilization to change marriage markets for particular cohorts. We use exogenous variation across states and over time in men drafted per 100 men 19-25 to look at the effects of the wartime mobilization on birth rates. We find robust evidence that higher rates of inducted men led to significantly lower birth rates.
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Marcus Tamm
Oxford Bulletin of Economics and Statistics, forthcoming
Abstract:
The introduction of the German parental leave benefit (Elterngeld) applied to all children born on 1 January, 2007 or later. The Elterngeld considerably changed the amount of transfers to families during the first two years postpartum. We show that the incentives created by using a cut-off date led more than 1,000 parents to postpone the delivery of their children from December 2006 to January 2007. Concerning potential adverse impacts on health outcomes of children we find a slight increase in average birth weight and the rate of children with high birth weight (>4,000 g).
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Julia Barthold, ikko Myrskylä & Owen Jones
Evolution and Human Behavior, forthcoming
Abstract:
The association between reproductive success and income in economically developed societies remains a controversial and understudied topic. The commonly made statement that individuals with a higher income have fewer children defies evolutionary explanation. Here we present results from an analyses of the association between lifetime reproductive success (LRS) and income for modern Europeans from 13 countries. We examine the relationships among income, partner income, sex and LRS, and the role of childlessness in driving the relationships. For women, we find a negative association between LRS and income, while for men, we find a flat or slightly positive one. The sex difference in the association appears to be driven by income's sex-specific association with childlessness; men with a low income have a relatively high risk of childlessness, while women with a low income have a low risk of childlessness. Consequently, once childless people are excluded from the analysis, LRS is negatively associated with income for both sexes. We argue that the observed LRS-income associations may be an outcome of evolved behavioural predispositions operating in modern environments and conclude that, even though humans fail to maximise LRS at all income levels in modern settings, evolutionary theory can still help to explain sex differences in LRS.
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Natalist Policies in the United States
Leonard Lopoo & Kerri Raissian
Journal of Policy Analysis and Management, forthcoming
Abstract:
This retrospective reviews the policies that affect the fertility of American women, both policies designed to alter fertility intentionally as well as those that change childbearing unintentionally. Becker's seminal work on the economics of fertility serves as the theoretical foundation for this literature. After describing Becker's economic model, we review the empirical literature on fertility responses to social welfare policies, tax policies, the mandated health care coverage of infertility treatments, abortion policies, and government-sponsored family planning services. We also address several Supreme Court cases that have played an important role in the interpretation of these policies. Where relevant, this retrospective describes the distributional effects of these natalist policies. We also discuss the limitations of this literature and identify important gaps. Unlike most developed countries that have created strategies to increase fertility to support their ageing population, the United States spends considerably less time and thought on this issue. Our reading of the literature suggests that we have many public policies that have affected and continue to influence the fertility choices made by families in the United States and that this is a topical area that deserves more attention in policy debates.
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Unintended Pregnancy and Induced Abortion in the Netherlands 1954-2002
Mark Levels et al.
European Sociological Review, June 2012, Pages 301-318
Abstract:
In the Netherlands, abortion is legal, safe, easily available, and free of charge. Paradoxically, it is also extremely rare. Little quantitative research into the Netherlands' abortion practice has been done. We analyse the fertile life-course of N = 3,793 Dutch women between 1954 and 2002. Using repeated event history analyses and sequential logistic regression, we test hypotheses on individual and societal effects on women's likelihood of experiencing (unintended) pregnancies and abortions during their life-course. The most important findings pertain to the effect of policies and laws intended to regulate reproductive behaviour. During the observation period, permissive abortion legislation and higher availability of abortion services increased the likelihood that Dutch women terminated unintended pregnancies. Abortion insurance did not affect the likelihood that women terminated an unintended pregnancy. Results suggest that the legalization, availability, and insurance of contraceptive pills helped to prevent abortions, because these measures effectively reduced the demand for abortion.
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Attitudes and Decision Making Among Women Seeking Abortions at One U.S. Clinic
Diana Greene Foster et al.
Perspectives on Sexual and Reproductive Health, June 2012, Pages 117-124
Context: Various restrictions on abortion have been imposed under the pretense that women may be uninformed, undecided or coerced in regard to their decision to terminate a pregnancy. Understanding whether certain women are at risk of low confidence in their abortion decision is useful for providing client-centered care and allocating counseling time to women with the greatest needs.
Methods: Data were abstracted from the precounseling needs assessment form and clinical intake form of 5,109 women who sought 5,387 abortions at one U.S. clinic in 2008. Multivariate logistic regression was used to analyze variables associated with women's high confidence in their abortion decision.
Results: For 87% of the abortions sought, women had high confidence in their decision before receiving counseling. Certain variables were negatively associated with abortions' being sought by women with high confidence: being younger than 20, being black, not having a high school diploma, having a history of depression, having a fetus with an anomaly, having general difficulty making decisions, having spiritual concerns, believing that abortion is killing and fearing not being forgiven by God (odds ratios, 0.2-0.8). Having a supportive mother or male partner was associated with increased odds of high confidence (1.3 and 1.2, respectively).
Conclusion: Regulations requiring state-approved information or waiting periods may not meet the complex needs of all women. Instead, women may benefit more from interactions with trained staff who can assess and respond to their individual needs.
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Dan Eisenberg, Geoffrey Hayes & Christopher Kuzawa
Proceedings of the National Academy of Sciences, forthcoming
Abstract:
Telomeres are repeating DNA sequences at the ends of chromosomes that protect and buffer genes from nucleotide loss as cells divide. Telomere length (TL) shortens with age in most proliferating tissues, limiting cell division and thereby contributing to senescence. However, TL increases with age in sperm, and, correspondingly, offspring of older fathers inherit longer telomeres. Using data and samples from a longitudinal study from the Philippines, we first replicate the finding that paternal age at birth is associated with longer TL in offspring (n = 2,023, P = 1.84 × 10-6). We then show that this association of paternal age with offspring TL is cumulative across multiple generations: in this sample, grandchildren of older paternal grandfathers at the birth of fathers have longer telomeres (n = 234, P = 0.038), independent of, and additive to, the association of their father's age at birth with TL. The lengthening of telomeres predicted by each year that the father's or grandfather's reproduction are delayed is equal to the yearly shortening of TL seen in middle-age to elderly women in this sample, pointing to potentially important impacts on health and the pace of senescent decline in tissues and systems that are cell-replication dependent. This finding suggests a mechanism by which humans could extend late-life function as average age at reproduction is delayed within a lineage.
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Shige Song
Proceedings of the Royal Society: Biological Sciences, 22 July 2012, Pages 2883-2890
Abstract:
The current study examined the long-term trend in sex ratio at birth between 1929 and 1982 using retrospective birth histories of 310 101 Chinese women collected in a large, nationally representative sample survey in 1982. The study identified an abrupt decline in sex ratio at birth between April 1960, over a year after the Great Leap Forward Famine began, and October 1963, approximately 2 years after the famine ended, followed by a compensatory rise between October 1963 and July 1965. These findings support the adaptive sex ratio adjustment hypothesis that mothers in good condition are more likely to give birth to sons, whereas mothers in poor condition are more likely to give birth to daughters. In addition, these findings help explain the lack of consistent evidence reported by earlier studies based on the 1944-1945 Dutch Hunger Winter or the 1942 Leningrad Siege.
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Trends of socioeconomic disparities in referral patterns for fertility preservation consultation
Linnea Goodman et al.
Human Reproduction, July 2012, Pages 2076-2081
Background: While oncologists are aware that cancer treatments may impact fertility, referral rates for fertility preservation consultation (FPC) remain poor. The goal of this study was to identify predictors associated with FPC referral.
Methods: This is a retrospective, cohort study of women aged 18-42 years diagnosed with a new breast, gynecologic, hematologic or gastrointestinal cancer at our institution between January 2008 and May 2010. Exclusion criteria included history of permanent sterilization, documentation of no desire for future children, stage IV disease, short interval (<4 days) between diagnosis and treatment and treatment that posed no threat to fertility. Demographic, socioeconomic and cancer variables were evaluated with respect to FPC. Logistic regression was used to determine the odds of referral for FPC based on specified predictors.
Results: One hundred and ninety-nine patients were eligible for FPC and of those, 41 received FPC (20.6%). Women with breast cancer were 10 times more likely to receive FPC compared with other cancer diagnoses [odds ratio (OR) 10.1; 95% confidence interval (CI) 3.8-26.8]. The odds of FPC referral were approximately two times higher for Caucasian women (OR 2.4; 95% CI 0.9-6.2), three times higher for age <35 years (OR 3.3; 95% CI 1.4-7.7) and four times higher in nulliparous women (OR 4.6; 95% CI 1.9-11.3). There was no association between BMI, income, distance to our institution, being in a relationship and referral for FPC.
Conclusions: Overall referral rates for FPC are low, and there appear to be significant discrepancies in referral based on ethnicity, age, parity and cancer type. This highlights a need for further provider education and awareness across all oncologic disciplines.
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Arturo Aguilar & Marta Vicarelli
Harvard Working Paper, November 2011
Abstract:
El Niño Southern Oscillation (ENSO) is a recurrent climatic event that causes severe weather shocks. This paper employs ENSO-related floods at the end of the agricultural season to identify medium-term effects of negative conditions in early child development. The analysis shows that, four to five years after the shock, children exposed to it during their early stages of life have test scores in language development, working-memory, and visual-spatial thinking abilities that are 11 to 21 percent lower than same aged children not exposed to the shock. Negative effects are also found on anthropometric characteristics: children affected during their early life stages exhibit lower height (0.42 to 0.71 inches), higher likelihood of stunting (11 to 14 percentage points), and lower weight (0.84 pounds) than same aged children not affected by the shock. Negative effects of weather shocks on income, food consumption, and diet composition during early childhood appear to be key mechanisms behind the impacts on children's outcomes. Finally, no mitigation effects were found from the provision of the Mexican conditional cash transfer program Progresa on poor rural households with children affected by ENSO-related shocks.
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Transitory Shocks and Birth Weights: Evidence from a Blackout in Zanzibar
Alfredo Burlando
University of Oregon Working Paper, May 2012
Abstract:
Do transitory economic shocks affect health? I show that an unexpected, month-long blackout in Tanzania caused a sharp but temporary drop in work hours for workers in electricity-dependent jobs. Using records from a maternity ward, I document a reduction in birth weights for children exposed in utero to the blackout, and an increase in the probability of low birth weight. The reduction is correlated with measures of maternal exposure to the blackout. Blackout-induced declines in maternal nutrition and maternal stress are the most likely causes. The blackout also increased births, but selection into pregnancy cannot fully explain the drop in weights.
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To know or not to know? Dilemmas for women receiving unknown oocyte donation
S.J. Stuart-Smith, J.A. Smith & E.J. Scott
Human Reproduction, July 2012, Pages 2067-2075
Background: This study aims to provide insight into the reasons for choosing an unknown oocyte donor and to explore recipients' feelings and wishes regarding donor information.
Methods: In-depth interviews were carried out with 11 women at different stages of treatment. Seven were on a waiting list and four have given birth to donor oocyte babies. The interviews were analysed using interpretative phenomenological analysis.
Results: The choice of unknown donor route was motivated by a wish to feel secure in the role of mother as well as to avoid possible intrusions into family relationships. The information that is available about unknown donors is often very limited. In the preconception phase of treatment, some participants wanted more information about the donor but others adopted a not-knowing stance that protected them from the emotional impact of needing a donor. In the absence of information that might normalize her, there was a tendency to imagine the donor in polarised simplistic terms, so she may be idealized or feared. Curiosity about the donor intensified once a real baby existed, and the task of telling a child was more daunting when very little was known about the donor. A strong wish for same-donor siblings was expressed by all of the participants who had given birth.
Conclusions: This qualitative study throws light on the factors that influence the choice of unknown donation. It also highlights the scope for attitudes to donor information to undergo change over the course of treatment and after giving birth. The findings have implications for pretreatment counselling and raise a number of issues that merit further exploration.
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Melanie Martin et al.
Maternal & Child Nutrition, July 2012, Pages 404-418
Abstract:
Breast milk fatty acid (FA) composition varies greatly among individual women, including in percentages of the long-chain polyunsaturated FAs (LCPUFA) 20:4n-6 (arachidonic acid, AA) and 22:6n-3 (docosahexaenoic acid, DHA), which are important for infant neurological development. It has been suggested that owing to wide variation in milk LCPUFA and low DHA in Western diets, standards of milk FA composition should be derived from populations consuming traditional diets. We collected breast milk samples from Tsimane women at varying lactational stages (6-82 weeks). The Tsimane are an indigenous, natural fertility, subsistence-level population living in Amazonia Bolivia. Tsimane samples were matched by lactational stage to samples from a US milk bank, and analysed concurrently for FA composition by gas-liquid chromatography. We compared milk FA composition between Tsimane (n = 35) and US (n = 35) mothers, focusing on differences in LCPUFA percentages that may be due to population-typical dietary patterns. Per total FAs, the percentages of AA, DHA, total n-3 and total n-6 LCPUFA were significantly higher among Tsimane mothers. Mean percentages of 18:2n-6 (linoleic acid) and trans FAs were significantly higher among US mothers. Tsimane mothers' higher milk n-3 and n-6 LCPUFA percentages may be due to their regular consumption of wild game and freshwater fish, as well as comparatively lower intakes of processed foods and oils that may interfere with LCPUFA synthesis.
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Shifts in color discrimination during early pregnancy
Levente Orbán & Farhad Dastur
Evolutionary Psychology, Spring 2012, Pages 238-252
Abstract:
The present study explores two hypotheses: a) women during early pregnancy should experience increased color discrimination ability, and b) women during early pregnancy should experience shifts in subjective preference away from images of foods that appear either unripe or spoiled. Both of these hypotheses derive from an adaptive view of pregnancy sickness that proposes the function of pregnancy sickness is to decrease the likelihood of ingestion of foods with toxins or teratogens. Changes to color discrimination could be part of a network of perceptual and physiological defenses (e.g., changes to olfaction, nausea, vomiting) that support such a function. Participants included 13 pregnant women and 18 non-pregnant women. Pregnant women scored significantly higher than non-pregnant controls on the Farnsworth-Munsell (FM) 100 Hue Test, an objective test of color discrimination, although no difference was found between groups in preferences for food images at different stages of ripeness or spoilage. These results are the first indication that changes to color discrimination may occur during early pregnancy, and is consistent with the view that pregnancy sickness may function as an adaptive defense mechanism.
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Mabel Lie et al.
Sociology of Health & Illness, June 2012, Pages 746-760
Abstract:
The termination of pregnancy trial (Newcastle upon Tyne, UK), is the only randomised trial on termination of pregnancy methods incorporating a qualitative element that aimed to understand the experiences of women participating in the trial. Based on the results of this qualitative work, this article aims to provide insights into two strands of understanding; firstly, women's experience of participating in research about abortion and secondly, their experience of participating in a randomised preference trial. Semi-structured interviews were conducted of up to 90 minutes with 30 participants recruited at a single hospital site. A total of 20 women from the preference arm and 10 from the random arm were interviewed. The analysis and discussion of our findings use reflexive modernisation as a framework for understanding and interpreting some of the actions of social agents, that is, the participants and trial recruiters in the course of a clinical trial as an expert system. We found that the factors that shape women's experiences and decisions include trust in the expert system and reflexivity and agency on the part of both participants and trial recruiters.
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Kelly Cleland et al.
Human Reproduction, July 2012, Pages 1994-2000
Background: Intrauterine devices (IUDs) have been studied for use for emergency contraception for at least 35 years. IUDs are safe and highly effective for emergency contraception and regular contraception, and are extremely cost-effective as an ongoing method. The objective of this study was to evaluate the existing data to estimate the efficacy of IUDs for emergency contraception.
Methods: The reference list for this study was generated from hand searching the reference lists of relevant articles and our own article archives, and electronic searches of several databases: Medline, Global Health, Clinicaltrials.gov, Popline, Wanfang Data (Chinese) and Weipu Data (Chinese). We included studies published in English or Chinese, with a defined population of women who presented for emergency contraception and were provided with an IUD, and in which the number of pregnancies was ascertained and loss to follow-up was clearly defined. Data from each article were abstracted independently by two reviewers.
Results: The 42 studies (of 274 retrieved) that met our inclusion criteria were conducted in six countries between 1979 and 2011 and included eight different types of IUD and 7034 women. The maximum timeframe from intercourse to insertion of the IUD ranged from 2 days to 10 or more days; the majority of insertions (74% of studies) occurred within 5 days of intercourse. The pregnancy rate (excluding one outlier study) was 0.09%.
Conclusions: IUDs are a highly effective method of contraception after unprotected intercourse. Because they are safe for the majority of women, highly effective and cost-effective when left in place as ongoing contraception, whenever clinically feasible IUDs should be included in the range of emergency contraception options offered to patients presenting after unprotected intercourse. This review is limited by the fact that the original studies did not provide sufficient data on the delay between intercourse and insertion of the IUD, parity, cycle day of intercourse or IUD type to allow analysis by any of these variables.