Maternal Stress and Child Outcomes: Evidence from Siblings

The impact of access to prenatal health insurance for noncitizen women on child health

OBJECTIVE

To estimate the effects of prenatal public health insurance targeting noncitizens on the health of U.S.-born children of noncitizen mothers beyond birth outcomes.

DATA SOURCES AND STUDY SETTING

This paper uses the restricted version of the 1998-2014 National Health Interview Survey with state-level geographic identifiers.

STUDY DESIGN

The empirical strategy compares outcomes in states that adopted the Children's Health Insurance Plan (CHIP) Unborn Child Option with states that never adopted or adopted it at different times, controlling for differences in the pre-treatment period. I use a flexible event-study analysis to quantify the effects of the Unborn Child Option on noncitizen women's health insurance coverage, health care utilization, and their children's health.

DATA COLLECTION/EXTRACTION METHODS

All data are derived from pre-existing sources.

PRINCIPAL FINDINGS

The study finds that the impact of the Unborn Child Option is a 4.7%-point increase in public health insurance coverage (p < 0.01) and 0.48 more doctor's office visits (p < 0.1) annually among noncitizens of childbearing ages. Subsequently, the reform leads to a 7%-point rise in the rate of parents reporting their 4-6-year-old children are in "excellent" or "very good" health (p < 0.01). While no improvements are evident at birth and at younger ages, observed health improvements begin to appear by preschool age.

CONCLUSIONS

The study contributes to the literature by providing evidence that certain benefits of in-utero public health insurance targeting noncitizens may appear several years after birth, specifically around preschool age.

Devo-Aging: Intersections Between Development and Aging

There are two fundamental questions in developmental biology. How does a single fertilized cell give rise to a whole body? and how does this body later produce progeny? Synchronization of these embryonic and postembryonic developments ensures continuity of life from one generation to the next. An enormous amount of work has been done to unravel the molecular mechanisms behind these processes, but more recently, modern developmental biology has been expanded to study development in wider contexts, including regeneration, environment, disease, and even aging. However, we have just started to understand how the mechanisms that govern development also regulate aging. This review discusses examples of signaling pathways involved in development to elucidate how their regulation influences healthspan and lifespan. Therefore, a better knowledge of developmental signaling pathways stresses the possibility of using them as innovative biomarkers and targets for aging and age-related diseases.

The COVID-19 pandemic and birth outcomes in 2020: The role of prenatal care and other channels

We use national birth data to assess the associations between the COVID-19 pandemic during 2020 and birth outcomes in Uruguay. Employing interrupted time series difference-in-differences techniques, we find mixed results, with some pregnancies showing increases in the likelihood of very preterm or very-low-weight births, and some others showing decreases in the incidence of moderate prematurity and moderate low birth weight. Adverse outcomes are more likely among women with low education, women with previous children, and with risk factors, such as smoking or being older than 34. We observe improvements in health at birth for children of non-smokers, women younger than 35, and women with no other children. We underscore the role of health care by showing that women in the private sector, who suffered the strongest contraction in face-to-face prenatal care use, experienced more adverse birth outcomes. Our results also suggest that the economic recession and an increased burden of childcare were behind the increases in preterm and very-low-weight births. Because pollution is an unlikely channel for the positive results, we hypothesize that for some pregnancies, the pandemic improved the intrauterine habitat by leading to a quieter and healthier lifestyle.

Maternal Distress during Pregnancy and the Postpartum Period: Underlying Mechanisms and Child's Developmental Outcomes-A Narrative Review

Maternal mental health may be considered a determining factor influencing fetal and child development. An essential factor with potentially negative consequences for a child's psychophysiological development is the presence of maternal distress during pregnancy and the postpartum period. The review is organized and presented to explore and describe the effects of anxiety, stress, and depression in pregnancy and the postpartum period on adverse child developmental outcomes. The neurobiology of maternal distress and the transmission mechanisms at the molecular level to the fetus and child are noted. In addition, the paper discusses the findings of longitudinal studies in which early child development is monitored concerning the presence of maternal distress in pregnancy and the postpartum period. This topic gained importance in the COVID-19 pandemic context, during which a higher frequency of maternal psychological disorders was observed. The need for further interdisciplinary research on the relationship between maternal mental health and fetal/child development was highlighted, especially on the biological mechanisms underlying the transmission of maternal distress to the (unborn) child, to achieve positive developmental outcomes and improve maternal and child well-being.

Maternal mental health and social support from online communities during pregnancy

Social determinants of public health have gained increasing attention. This paper studied whether social support from online communities related to maternal mental health. We focused on online maternity communities that group users with a similar prenatal status to facilitate their exchange of personal experiences and knowledge about maternal caring during pregnancy. Such online maternity communities are getting increasingly popular and can be found across countries and societies. We invited users-currently pregnant and gave birth within 1 year at the time of the study-from one such community in China to participate in a survey. The survey measured their perceived social support (PSS) exclusively from the peer group in the online community, their mental health and newborns' birth outcomes (N = 500). Users reported high score in PSS from the online peer group which was comparable to the ones from family, significant other and friends in other studies. We used linear regression models to examine the effects of PSS on mental health and birth outcomes. We found that a one-point increase in the PSS score was associated with a 0.19-point (p < 0.1) decrease in the prenatal depression and a 0.26-point (p < 0.01) decrease in the postnatal depression, which was equivalent to 3% and 4.5% of the average respectively. Moreover, a one-point increase in the PSS score was associated with a 14.49-gram increase in a newborn's weight (p < 0.01).

Genetic basis of cannabis use: a systematic review

BACKGROUND

With the increase in cannabis use rates, cannabis use disorder is being reported as one of the most common drug use disorders globally. Cannabis use has several known physical, psychological, and social adverse events, such as altered judgement, poor educational outcomes, and respiratory symptoms. The propensity for taking cannabis and the development of a cannabis use disorder may be genetically influenced for some individuals. Heritability estimates suggest a genetic basis for cannabis use, and several genome-wide association studies (GWASs) have identified possible regions of association, albeit with inconsistent findings. This systematic review aims to summarize the findings from GWASs investigating cannabis use and cannabis use disorder.

METHODS

This systematic review incorporates articles that have performed a GWAS investigating cannabis use or cannabis use disorder. MEDLINE, Web of Science, EMBASE, CINAHL, GWAS Catalog, GWAS Central, and NIH Database of Genotype and Phenotype were searched using a comprehensive search strategy. All studies were screened in duplicate, and the quality of evidence was assessed using the quality of genetic association studies (Q-Genie) tool. All studies underwent qualitative synthesis; however, quantitative analysis was not feasible.

RESULTS

Our search identified 5984 articles. Six studies met our eligibility criteria and were included in this review. All six studies reported results that met our significance threshold of p ≤ 1.0 × 10-7. In total 96 genetic variants were identified. While meta-analysis was not possible, this review identified the following genes, ANKFN1, INTS7, PI4K2B, CSMD1, CST7, ACSS1, and SCN9A, to be associated with cannabis use. These regions were previously reported in different mental health conditions, however not in relation to cannabis use.

CONCLUSION

This systematic review summarized GWAS findings within the field of cannabis research. While a meta-analysis was not possible, the summary of findings serves to inform future candidate gene studies and replication efforts. Systematic Review Registration PROSPERO CRD42020176016.

Ethnic Violence and Birth Outcomes: Evidence From Exposure to the 1992 Conflict in Kenya

This study is an examination of the effect of intrauterine exposure to electoral violence on child birth weight, an outcome that has long-term effects on an individual's education, income, and health in later life. We consider the electoral violence that resulted from the introduction of multiparty democracy in Kenya as an exogenous source of shock, using a difference-in-differences method and a mother fixed-effects model. We find that prenatal exposure to the violence increased the probabilities of low birth weight and a child being of very small size at birth by 19 and 6 percentage points, respectively. Violence exposure in the first trimester of pregnancy decreased birth weight by 271 grams and increased the probabilities of low birth weight and very small size at birth by 18 and 4 percentage points, respectively. The results reaffirm the significance of the nine months in utero as one of the most critical periods in life that shapes future health, economic, and educational trajectories.

Maternal exposure to a high-magnitude earthquake during pregnancy influences pre-reading skills in early childhood

Exposure to an adverse prenatal environment can influence fetal development and result in long-lasting changes in the offspring. However, the association between maternal exposure to stressful events during pregnancy and the achievement of pre-reading skills in the offspring is unknown. Here we examined the association between prenatal exposure to the Chilean high-magnitude earthquake that occurred on February 27th, 2010 and the development of early reading precursors skills (listening comprehension, print knowledge, alphabet knowledge, vocabulary, and phonological awareness) in children at kindergarten age. This multilevel retrospective cohort study including 3280 children, of whom 2415 were unexposed and 865 were prenatally exposed to the earthquake shows substantial evidence that maternal exposure to an unambiguously stressful event resulted in impaired pre-reading skills and that a higher detrimental effect was observed in those children who had been exposed to the earthquake during the first trimester of gestation. In addition, females were more significantly affected by the exposure to the earthquake than their male peers in alphabet knowledge; contrarily, males were more affected than females in print knowledge skills. These findings suggest that early intervention programs for pregnant women and/or children exposed to prenatal stress may be effective strategies to overcome impaired pre-reading skills in children.

Postpartum stress and protective factors in women who gave birth in the United States during the COVID-19 pandemic

OBJECTIVES

The COVID-19 pandemic has caused considerable stress throughout the world. Little is known about how postpartum women who gave birth during the early months of the pandemic were impacted. The purpose of this study was to explore and describe the associations between potential risk, protective factors, and psychological distress among postpartum women who gave birth during the early months of the COVID-19 pandemic.

METHODS

Postpartum women over the age of 18 years who gave birth in the US hospitals between March and July of 2020 and spoke English completed a survey about their experiences. Demographic and health variables were measured via self-report. Stress was measured using the Perceived Stress Scale-10. Mastery was measured with the Pearlin Mastery Scale. Resilience was measured with the Connor-Davidson Resilience Scale-2.

RESULTS

This study included 885 women. Participants had higher stress and lower resilience relative to pre-pandemic norms. Participants had high levels of depression, anxiety, and stress. Women who had an infant admitted to the neonatal intensive care unit had more stress. Income, full-time employment, and partnered relationships were associated with lower stress. Resilience and mastery were related to lower stress, depression, and anxiety. Black, Indigenous, or People of Color women showed higher stress and lower resiliency. Single women were likely to report lower levels of mastery than partnered women.

CONCLUSION

Stress, depression, and anxiety were high in postpartum women in this study. Income, partnered relationships, and employment security, along with protective traits such as mastery and resilience, may reduce the impact of stress on postpartum women in a pandemic. Care models should be modified to support women during a pandemic. Health disparities exist in postpartum stress. Future interventions should focus on building resiliency and mastery and ensuring appropriate resources are available to postpartum women in a pandemic.

Does Maternal Depression Undermine Childhood Cognitive Development? Evidence from the Young Lives Survey in Peru

This paper studies the effect of maternal depression on early childhood cognition in Peru, where rates of depression are around 50%. By using an instrumental variables approach, this study exploits variation in the exogeneity of the exposure to shocks during early life to instrument for maternal depression. The empirical strategy exploits a novel longitudinal data-the Young Lives survey-that includes information on cognitive outcomes of children and variation in their mothers' mental health status between rounds of data collection. Results suggest that maternal depression is detrimental to a child's vocabulary at age 5, but effects fade out by age 8. Effects do not vary by maternal education but are significant only for children living in disadvantaged households. Estimations indicate that the presence of a partner worsens the effect of maternal depression on vocabulary development, results that are driven mainly by households with heavy-drinking partners. Our findings make a strong case for recognizing maternal mental health problems as disorders of public health significance and guide maternal and infant health policies in Peru.

Associations between prenatal sunshine exposure and birth outcomes in China

This paper is one of the first to examine the associations between prenatal sunshine exposure and birth outcomes, specifically the incidence of low birth weight (LBW) and small for gestational age (SGA), based on a nationally representative birth record dataset in China. During the sample period in the 1990s, migration was limited in rural China, allowing us to address the identification challenges, like residential sorting and avoidance behaviors. We found a nonlinear relationship between the length of sunlight and birth outcomes. In particular, prenatal exposure to increasing sunshine was associated with a reduction in the incidence of LBW and SGA, especially in the second trimester during pregnancy. This finding was consistent with the clinical evidence suggesting positive effects of sunshine on birth outcomes via obtaining vitamin D or relieving maternal stress.

Prenatal anxiety, breastfeeding and child growth and puberty: linking evolutionary models with human cohort studies

Background: Stress experienced by mothers during pregnancy can have both immediate and long-term effects on child development, potentially mediated by breastfeeding.Aim: Using a UK birth cohort study, we asked how maternal stress relates to breastfeeding and consequences for growth and puberty onset.Subjects and methods: We analysed data from the Avon Longitudinal Study of Parents and Children, collected via questionnaires and clinic visits (N: 698-8,506). We used reports of prenatal anxiety, breastfeeding, early growth and age at menarche or first voice change. Confounding by maternal age, parity, smoking, education and body mass index (BMI) was considered.Results: Mothers with higher levels of reported anxiety were less likely to breastfeed (Odds ratio (OR): 0.83, 95% confidence interval (CI): 0.71, 0.97). Breastfed infants had slower growth before weaning, although growth differences were unclear thereafter. Being breastfed for more than six months was associated with later puberty onset in females (2.76 months later than non-breastfed; CI: 0.9, 4.63), although the association was attenuated by confounders and BMI (1.51 months, CI: -0.38, 3.40). No association between breastfeeding and puberty onset in males was found.Conclusion: Our studies fit results shown previously, and we consider these in light of evolutionary life history theory while discussing key challenges in such an approach.

Stress beyond coping? A Rasch analysis of the Perceived Stress Scale (PSS-14) in an Aboriginal population

The history of colonization contributed to Aboriginal and Torres Strait Islanders becoming one of the most disadvantaged groups in Australia. The multiple social inequalities, and therefore the constant insecurities for many about low income, poor living conditions, unemployment, and discrimination, generate chronic stress in this population. In the Baby Teeth Talk Study, an oral-health randomized controlled trial, the Perceived Stress Scale (PSS-14) was administered to 367 pregnant Aboriginal women at baseline. The aim of the present study was to evaluate the validity and reliability of the PSS-14 in an Aboriginal population. The study analysed: (a) model fit; (b) dimensionality; (c) local dependence; (d) differential item functioning; (e) threshold ordering and item fit; (f) targeting; (g) reliability; and (h) criterion validity. The dimensionality analysis indicated a two-factor structure, with negatively and positively worded items clustering together and 21.7% (95% Agresti-Coull C.I. [17.8%, 26.2%]) statistically significant t-tests between the persons' estimates. After the creation of composite items, the revised Perceived Distress (χ2 (21) = 11.74, p = 0.946) and Perceived Coping (χ2 (28) = 17.63, p = 0.935) subscales fitted the Rasch model. Reliability was modest (PersonSeparationIndexdistress = 0.72; PersonSeparationIndexcoping = 0.76). The latent correlation between the Perceived Distress and Perceived Coping subscales was r = 0.14. It is hypothesized that the social inequalities experienced by the Aboriginal population are so pronounced that even Aboriginal pregnant women that perceived themselves as coping well with life challenges ended up endorsing items regarding high levels of stress. The present research showed that a revised PSS-14 is a culturally valid and modestly reliable psychological instrument to measure stress in a population of pregnant Aboriginal women in Australia.

US acculturation and poor sleep among an intergenerational cohort of adult Latinos in Sacramento, California

Acculturation may shape the disproportionate burden of poor sleep among Latinos in the United States. Existing studies are limited by unidimensional acculturation proxies that are incapable of capturing cultural complexities across generations. Understanding how acculturation relates to sleep may lead to the identification of modifiable intervention targets. We used multivariable regression and latent class methods to examine cross-sectional associations between a validated multidimensional scale of US acculturation and self-reported poor sleep measures. We analyzed an intergenerational cohort: first-generation (GEN1) older Latinos (Sacramento Area Latino Study on Aging; N = 1,716; median age: 69.5) and second-generation (GEN2) middle-aged offspring and relatives of GEN1 (Niños Lifestyle and Diabetes Study; N = 670; median age: 54.0) in Sacramento, California. GEN1 with high US acculturation, compared with high acculturation towards another origin/ancestral country, had less restless sleep (prevalence ratio [PR] [95% confidence interval (CI)]: 0.67 [0.54, 0.84]) and a higher likelihood of being in the best sleep class than the worst (OR [95% CI]: 1.62 [1.09, 2.40]), but among nonmanual occupations, high intergenerational US acculturation was associated with more general fatigue (PR [95% CI: 1.86 [1.11, 3.10]). GEN2 with high intergenerational US acculturation reported shorter sleep (PR [95% CI]: 2.86 [1.02, 7.99]). High US acculturation shaped sleep differentially by generation, socioeconomic context, and intergenerational acculturative status. High US acculturation was associated with better sleep among older, lower socioeconomic Latinos, but with shorter sleep duration among middle-aged, higher socioeconomic Latinos; results also differed by parental acculturation status. Upon replication, future studies should incorporate prospective and intergenerational designs to uncover sociobehavioral pathways by which acculturation may shape sleep to ultimately inform intervention efforts.

Maternal employment and child health in Nepal: The importance of job type and timing across the child's first five years

The increase in female labor force participation (FLFP) in the paid labor market since the mid-1900s is one of the most pronounced family transitions and increasingly a global phenomenon. While this may improve income and bargaining power of the women, it may also increase stress and decrease time with children. Using the Chitwan Valley Family Study in Nepal, we explore the consequences of this transition for children's health by combining newly collected data on child health outcomes, quarterly data on women's employment, and data on households and neighborhoods. Regression models were used to estimate the relationship between FLFP and child health, exploring both the type (wage, salary, or own business) and timing of work across the child's first five years for 860 children born to 793 mothers. After adjusting for a robust set of individual, household, and community factors, FLFP is associated with worse child health. We find evidence this is largely due to wage labor, the more common but "lower quality" and lower paying type of work women do. Measures of current work are generally inadequate at capturing this negative relationship. Breastfeeding may be an important piece of this story as mothers that worked during the first six months of a child's life were less likely to exclusively breastfeed during this period. Recognizing the challenges faced by working mothers in LMICs and paying attention to the quality of work will be critical as more women enter the workforce.

Maternal smoking during pregnancy and offspring personality in childhood and adulthood

OBJECTIVE

Maternal smoking during pregnancy (MSDP) has been associated with offspring internalizing and externalizing disorders. The purpose of this research is to examine whether MSDP is also associated with variations in normal personality traits in childhood and adulthood.

METHOD

This study uses four independent samples (total N = 16,323) to examine whether there are mean-level differences in offspring personality traits by MSDP, controlling for relevant sociodemographic factors. Two samples are of children (Ns = 3,782 and 3,841) and two samples are of adults (Ns = 1,786 and 6,914).

RESULTS

A meta-analysis across the four samples indicated that offspring of mothers who did smoke during pregnancy scored higher in Neuroticism (p = .000) and Extraversion (p = .003) and lower in Conscientiousness (p = .002) than offspring of mothers who did not smoke during pregnancy. The association between MSDP and Neuroticism and Conscientiousness held across both childhood and adulthood and when propensity score matching was used, whereas the association with Extraversion was only apparent in adulthood and did not hold with propensity scores.

CONCLUSIONS

These results suggest that MSDP is associated with individual differences in psychological traits in childhood and adulthood and may be one prenatal factor that contributes to trait Neuroticism and Conscientiousness.

Effects of state-level Earned Income Tax Credit laws in the U.S. on maternal health behaviors and infant health outcomes

The purpose of this paper is to investigate the effects of state-level Earned Income Tax Credit (EITC) laws in the U.S. on maternal health behaviors and infant health outcomes. Using multi-state, multi-year difference-in-differences analyses, we estimated effects of state EITC generosity on maternal health behaviors, birth weight and gestation weeks. We find little difference in maternal health behaviors associated with state-level EITC. In contrast, results for key infant health outcomes of birth weight and gestation weeks show small improvements in states with EITCs, with larger effects seen among states with more generous EITCs. Our results provide evidence for important health benefits of state-level EITC policies.

Specification of Change Mechanisms in Pregnant Smokers for Malleable Target Identification: A Novel Approach to a Tenacious Public Health Problem

Maternal smoking during pregnancy (MSDP) continues to be a leading modifiable risk factor for perinatal complications and a range of neurodevelopmental and cardio-metabolic outcomes across the lifespan. Despite 40 years of intervention research less than one in five pregnant smokers who receive an intervention quit by delivery. Within this context, recognition of pregnancy is commonly associated with abrupt suspension or reduction of smoking in the absence of intervention, yet has not been investigated as a volitional target. The goal of this article is to provide the empirical foundation for a novel direction of research aimed at identifying malleable targets for intervention through the specification of behavior change mechanisms specific to pregnant women. To do so, we: (1) summarize progress on MSDP in the United States generated from conventional empirical approaches to health behavior change; (2) discuss the phenomenon of spontaneous change in the absence of intervention among pregnant smokers to illustrate the need for mechanistic specification of behavior change motivated by concern for fetal well-being; (3) summarize component processes in neurobiological models of parental and non-parental social behaviors as a conceptual framework for understanding change mechanisms during pregnancy; (4) discuss the evidence for the malleability of these processes to support their translational relevance for preventive interventions; and (5) propose a roadmap for validating the proposed change mechanism using an experimental medicine approach. A greater understanding of social and interpersonal processes that facilitate health behavior change among expectant mothers and how these processes differ interindividually could yield novel volitional targets for prenatal interventions. More broadly, explicating other-oriented mechanisms of behavior change during pregnancy could serve as a paradigm for understanding how social and interpersonal processes positively influence health behaviors across the lifespan.

The Role of Children's Health in the Intergenerational Transmission of Economic Status

Intergenerational mobility is relatively low in the United States. Children who grow up in poverty are eight times more likely to live in poverty in adulthood than their counterparts who do not live in poverty. What is it about growing up in poverty that reduces the probability of economic success later in life? On average, children whose families live in poverty have lower levels of cognitive skills, noncognitive skills (e.g., behavior including perseverance and adaptability), and health, all of which contribute to earnings in adulthood. In this article, I examine the role children's health plays in intergenerational transmission of economic status from an economic perspective and in the context of a developed, high‐income country (the United States). Evidence suggests that the mechanisms by which parents’ income affects children's health include, but are not limited to, reduced access to health insurance and medical care, greater exposure to environmental toxins, inadequate nutrition, and greater family violence and stress. I conclude with evidence suggesting that public investments in children's health can reduce the intergenerational transmission of economic status and the inequality of the next generation in the United States, as well as in other less developed nations.

Does MAOA increase susceptibility to prenatal stress in young children?

BACKGROUND

We previously demonstrated a gene-by-prenatal-environment interaction whereby the monoamine oxidase A gene (MAOA) modified the impact of prenatal tobacco exposure (PTE) on adolescent disruptive behavior (DB), with the MAOA risk genotype varying by sex. We extend this work by examining whether this mechanism is evident with another common adversity, prenatal stress exposure (PSE), and whether sex differences are present earlier in development in closer proximity to exposure.

METHODS

Participants were 281 mothers and their 285 children derived from a prenatal cohort with in-depth prospective measures of PSE and PTE. We assessed DB at age 5 via dimensional developmentally-sensitive measurement. Analyses were stratified by sex based on prior evidence for sex differences.

RESULTS

Concurrent stress exposure predicted DB in children (β=0.310, p=0.001), while main effects of prenatal exposures were seen only in boys. We found a three-way interaction of MAOA×PSE×sex on DB (β=0.813, p=0.022). Boys with MAOA-H had more DB as a function of PSE, controlling for PTE (β=0.774, p=0.015), and as a function of PTE, controlling for PSE (β=0.362, p=0.037). Boys with MAOA-L did not show this susceptibility. MAOA did not interact with PSE (β=-0.133, p=0.561) nor PTE (β=-0.144; p=0.505) in predicting DB in girls. Examination of gene-environment correlation (rGE) showed a correlation between paternal MAOA-L and daughters' concurrent stress exposure (r=-0.240, p=0.013).

DISCUSSION

Findings underscore complex mechanisms linking genetic susceptibility and early adverse exposures. Replication in larger cohorts followed from the pregnancy through adolescence is suggested to elucidate mechanisms that appear to have varying developmental expression.

Maternal employment during pregnancy and birth outcomes: evidence from Danish siblings

I use Danish survey and administrative data to examine the impact of maternal employment during pregnancy on birth outcomes. As healthier mothers are more likely to work and health shocks to mothers may impact employment and birth outcomes, I combine two strategies: First, I control extensively for time-varying factors that may correlate with employment and birth outcomes, such as pre-pregnancy family income and maternal occupation, pregnancy-related health shocks, maternal sick listing, and health behaviors (smoking and alcohol consumption). Second, to account for remaining time-invariant heterogeneity between mothers, I compare outcomes of mothers' consecutive children. Mothers who work during the first pregnancy trimester have a lower risk of preterm birth. I find no effect on the probability of having a baby of small size for gestational age. To rule out that health selection of mothers between pregnancies drives the results, I focus on mothers whose change in employment status is likely not to be driven by underlying health (mothers who are students in one of their pregnancies and mothers with closely spaced births). Given generous welfare benefits and strict workplace regulations in Denmark, my findings support a residual explanation, namely, that exclusion from employment may stress mothers in countries with high-female employment rates.

The intergenerational transmission of inequality: maternal disadvantage and health at birth

Health at birth is an important predictor of long-term outcomes, including education, income, and disability. Recent evidence suggests that maternal disadvantage leads to worse health at birth through poor health behaviors; exposure to harmful environmental factors; worse access to medical care, including family planning; and worse underlying maternal health. With increasing inequality, those at the bottom of the distribution now face relatively worse economic conditions, but newborn health among the most disadvantaged has actually improved. The most likely explanation is increasing knowledge about determinants of infant health and how to protect it along with public policies that put this knowledge into practice.