Intergenerational health consequences of in utero exposure to maternal stress: Evidence from the 1980 Kwangju uprising

Early life exposure to cold weather shocks and growth stunting: Evidence from Tanzania

This study examines the effects of early life and in utero exposure to cold weather shocks on the incidence of growth stunting for children under age five in Tanzania. We find that an increase of 10 percentage points in the proportion of days with temperatures below 15 degrees Celsius (one standard deviation below the long-term average) is associated with an increase in the probability of stunting and severe stunting by 2.0 and 1.4 percentage points (equivalent to 5.5 and 9.7 percent of the mean stunting and severe stunting), respectively. The results also show strong effects of in utero exposure during the second trimester of pregnancy on child stunting and wasting. In terms of the mechanisms, we find that the effects on disease environment, food insecurity, and reduced agricultural productivity are the possible channels driving the results.

Stillbirths, miscarriages and early losses in armed conflict contexts. The modification effect of violence. The Colombian case

BACKGROUND

Colombia experienced a prolonged armed conflict that affected differently regions and periods. We explored how this regional violence influenced the well-being of newborns, using data from the National Centre of Historic Memory (NCHM) and the Vital Statistics Survey. The NCHM recorded the number of victims, while the Vital Statistics Survey reported data on births, stillbirths, and early losses.

AIM

We aimed to assess the impact of regional violence on newborns' well-being and to examine whether mothers' university education mitigated these effects. We focused on comparing two periods: 1998-2002 and 2003-2007, and two group of regions which differed in the intensity and distribution of violence.

METHODS

We applied a difference-in-differences approach and logistic regression analysis to estimate the odds of stillbirths and miscarriages in regions exposed to violence during the treated regions. We also estimated the interaction effect between treated groups and mothers' university education.

FINDINGS

We found a significant association between living in the most violent regions and having a higher risk of stillbirths, miscarriages, or early losses (OR: 1.721). Women living in less affected regions had a higher probability of giving birth to live babies and preserving the dyad. However, we observed a negative modifier effect of violence on the likelihood of live births for mothers with university education (OR:1.273).

DISCUSSION

We observed that the effect modification points to a higher impact of stress on mothers with university education in violent regions and periods compared to those without higher education. These findings unveil the concealed impact of regional violence, which diminishes the protective influence of maternal education, regardless of the level attained.

PROBLEM

The scarcity of empirical evidence regarding the causa through which violence modify the shield effect of university education in most affected areas.

WHAT IS ALREADY KNOWN

When women are able to complete their university education before giving birth, they are better able to have healthier pregnancies and therefore achieve higher levels of well-being for their newborns.

WHAT THIS PAPER ADDS

Pregnant women with university education are likely to be experiencing higher levels of stress compared to those mother with no university education within the most violent regions and periods embedded in armed conflict environments/contexts.

Opioids ease my pain: Early-life malnutrition and elderly outcomes

Despite a large body of evidence showing that early-life malnutrition influences adult outcomes, there is no evidence that early-life starvation causes use of opioids. Studying the long-term effects of a food shortage in Iran caused by WWII, we find that the rate of people who use drugs in this cohort increased significantly higher than in surrounding cohorts. Then, we examine a broad spectrum of outcomes for this cohort to shed light on potential causes of opioid use in the survivors of this cohort. Our findings suggest that pain contributes significantly to opioid use.

Can Universal Cash Transfer Save Newborns' Birth Weight During the Pandemic?

Birth weight is a key human biological characteristic as a measure of prenatal development and a variable related to later quality of life. Studies have firmly established that a stressful situation in utero adversely affects newborns' birth weight. Using birth statistics provided by Statistics Korea, this study examined how universal cash transfer during the COVID-19 crisis affected newborns' birth weight in South Korea. Given that the normal gestation period is nearly 10 months, we chose newborns without a self-selection issue by utilizing information on birthdate and total pregnancy period from the dataset, subsequently applying difference-in-differences estimation. Results showed that universal cash transfer offset newborns' weight loss amid the COVID-19 pandemic. The effects differed according to households' sociodemographic characteristics, with effects being more pronounced for girls; more pronounced for households with more than two children; more pronounced in local districts severely affected during the initial stage of the pandemic, but less significant in metropolitan regions; and more among middle-class families. This study presents evidence that governmental cash transfer during the pandemic has improved newborns' health and that continuing such a policy would positively impact future generations from a health perspective.

The effects of negative economic shocks at birth on adolescents’ cognitive outcomes and educational attainment in Malawi

We provide new evidence of the association between moderate negative economic shocks in utero or shortly after birth and adolescents’ cognitive outcomes and educational attainment in Malawi. This is one of the first studies to analyze the effect of not one, but multiple moderate negative economic shocks in a sub-Saharan African (SSA) low-income country (LIC). This focus is important as multiple economic shocks in early life are more representative of the experiences of adolescents in LICs. Combining data on adolescents aged 10–16 from the Adverse Childhood Experiences (ACE) project with the Malawi Longitudinal Study on Families and Health (MLSFH) (N = 1, 559), we use linear and probit regression models to show that girls whose households experienced two or more economic shocks in their year of birth have lower cognitive scores, which are measured using working memory, reading and mathematical tests. Girls also have lower educational attainment, conditional on age. These effects are gendered, as we do not observe similar effects among boys. Overall, our results point to lasting effects of early-life adversity on adolescents, and they highlight that, even in a LIC context where early-life adversity is common, policymakers need to intervene early to alleviate the potential long-term educational impacts of in utero or early life shocks among girls.

Prenatal phthalate exposure in relation to placental corticotropin releasing hormone (pCRH) in the CANDLE cohort

CONTEXT

Phthalates may disrupt maternal-fetal-placental endocrine pathways, affecting pregnancy outcomes and child development. Placental corticotropin releasing hormone (pCRH) is critical for healthy pregnancy and child development, but understudied as a target of endocrine disruption.

OBJECTIVE

To examine phthalate metabolite concentrations (as mixtures and individually) in relation to pCRH.

DESIGN

Secondary data analysis from a prospective cohort study.

SETTING

Prenatal clinics in Tennessee, USA.

PATIENTS

1018 pregnant women (61.4% non-Hispanic Black, 32% non-Hispanic White, 6.6% other) participated in the CANDLE study and provided data. Inclusion criteria included: low-medical-risk singleton pregnancy, age 16-40, and gestational weeks 16-29.

INTERVENTION

None.

MAIN OUTCOME MEASURES

Plasma pCRH at two visits (mean gestational ages 23.0 and 31.8 weeks) and change in pCRH between visits (ΔpCRH).

RESULTS

In weighted quantile sums (WQS) regression models, phthalate mixtures were associated with higher pCRH at Visit 1 (β = 0.07, 95 %CI: 0.02, 0.11) but lower pCRH at Visit 2 (β = -0.08, 95 %CI: -0.14, -0.02). In stratified analyses, among women with gestational diabetes (n = 59), phthalate mixtures were associated with lower pCRH at Visit 1 (β = -0.17, 95 %CI: -0.35, 0.0006) and Visit 2 (β = -0.35, 95 %CI: -0.50, -0.19), as well as greater ΔpCRH (β = 0.16, 95 %CI: 0.07, 0.25). Among women with gestational hypertension (n = 102), phthalate mixtures were associated with higher pCRH at Visit 1 (β = 0.20, 95 %CI: 0.03, 0.36) and Visit 2 (β = 0.42; 95 %CI: 0.19, 0.64) and lower ΔpCRH (β = -0.17, 95 %CI: -0.29, -0.06). Significant interactions between individual phthalate metabolites and pregnancy complications were observed.

CONCLUSIONS

Phthalates may impact placental CRH secretion, with differing effects across pregnancy. Differences in results between women with and without gestational diabetes and gestational hypertension suggest a need for further research examining whether women with pregnancy complications may be more vulnerable to endocrine-disrupting effects of phthalates.

Transgenerational health effects of in utero exposure to economic hardship: Evidence from preindustrial Southern Norway

We studied whether in utero exposure to economic hardship during a grandmother's pregnancy has a transgenerational effect on her grandchildren's health condition. We used an individual-level three-generation data set covering people born between 1734 and 1840 in the municipality of Rendalen in Norway. We found a culling effect in which grandchildren whose grandmothers gave birth in years of economic hardship lived approximately ten years longer than grandchildren whose mothers were born in years of economic well-being. This impact was only observed among the grandmothers who belong to the lowest social classes. Our results also showed that in higher social classes, economic hardship during a grandmother's pregnancy deteriorated her grandchildren's health by "scarring" the mother's health.

Maternal stress during pregnancy and early childhood development

We estimate the impact of prenatal stress on early childhood development outcomes known as "middle years" or intermediate outcomes, which has not been studied previously. Using a unique measure of actual maternal stress induced by a large earthquake, we find that relative to children that were not exposed, in utero maternal stress reduces children's cognitive skills and socio-emotional problems by age 3, and that the effects are heterogeneous. The negative impacts on cognitive skills occur during the first trimester of pregnancy and are found among both low and high-income children, and boys and girls. The harmful effects on socio-emotional behaviors occur when stress is experienced in the last trimester of pregnancy.

The Impact of Early-Life Exposures on Women's Reproductive Health in Adulthood

Purpose of Review

To review the effects of early-life, preconception, and prior-generation exposures on reproductive health in women.

Recent Findings

Women’s early-life factors can affect reproductive health by contributing to health status or exposure level on entering pregnancy. Alternately, they can have permanent effects, regardless of later-life experience. Nutrition, social class, parental smoking, other adverse childhood experiences, environmental pollutants, infectious agents, and racism and discrimination all affect reproductive health, even if experienced in childhood or in utero. Possible transgenerational effects are now being investigated through three- or more-generation studies. These effects occur with mechanisms that may include direct exposure, behavioral, endocrine, inflammatory, and epigenetic pathways.

Summary

Pregnancy is increasingly understood in a life course perspective, but rigorously testing hypotheses on early-life effects is still difficult. In order to improve the health outcomes of all women, we need to expand our toolkit of methods and theory.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40471-021-00279-0.

Maternal stress during pregnancy and children's diet: Evidence from a population of low socioeconomic status

OBJECTIVES

This study examined the relationship between maternal exposure to stress during pregnancy and children's food preferences and diet in a population of low socioeconomic status.

METHODS

Indices of exposure to stress were constructed based on retrospective self-reported experience of stressful events during pregnancy (e.g., death of close family member, relationship difficulties, legal issues, health issues, financial issues, or other potentially stressful event[s]). Data were collected for >200 mothers of a low socioeconomic status with a child age 2 to 12 y. Data on mothers' body mass index, current exposure to stress, current diet, and diet during pregnancy were collected at the same time, as well as data on children's food preferences and current diet as reported by the mothers. Indices of the healthiness of food preferences and diet were constructed and used as outcome variables.

RESULTS

Maternal exposure to stress during pregnancy significantly predicts children's food and taste preferences, as well as their diet, in regression models controlling for maternal diet, current maternal stress, and demographic characteristics of both the child and mother. Higher average stress during pregnancy is linked with significantly less healthy food preferences and diet, as well as with weaker preferences for sour and bitter foods. This relationship is observed across different age groups.

CONCLUSIONS

Maternal exposure to stress during pregnancy could have long-term detrimental effects on dietary outcomes and thereby on health conditions related to diet. Prenatal care and preconception counseling could be critical to develop preventive strategies to improve public health.

Baby bonus in Switzerland: Effects on fertility, newborn health, and birth-scheduling

This paper studies the effect of birth allowances (so-called baby bonus) on fertility, newborn health, and birth-scheduling in Switzerland. Switzerland provides an optimal quasi-experiment: 11 out of 26 cantons introduced a baby bonus during the last 50 years at different points in time. To identify the effect of changes in the baby bonus, we employ an event study with control groups using several administrative data sets on births, stillbirths, and infant deaths in Switzerland from 1969 to 2017. While there is no evidence for birth-scheduling, we find, however, a sizable but only temporary increase in the fertility rate of 5.5% and a permanent but diminishing increase in the birth weight of 2.8%. The latter effect is particularly strong at the lower end of the birth weight distribution. Furthermore, we document substantial heterogeneity by citizenship of mothers.

Maternal stress and birth outcomes: Evidence from an unexpected earthquake swarm

We examine the impact of a major earthquake that unexpectedly affected the Canterbury region of New Zealand on a wide-range of birth outcomes, including birth weight, gestational age, and an indicator of general newborn health. We control for observed and unobserved differences between pregnant women in the area affected by the earthquake and other pregnant women by including mother fixed effects in all of our regression models. We extend the previous literature by comparing the impact of the initial unexpected earthquake to the impacts of thousands of aftershocks that occurred in the same region over the 18 months following the initial earthquake. We find that exposure to these earthquakes reduced gestational age, increased the likelihood of having a late birth, and negatively affected newborn health-with the largest effects for earthquakes that occurred in the first and third trimesters of pregnancy. Our estimates are similar when we focus on just the impact of the initial earthquake or, in contrast, on all earthquakes controlling for endogenous location decisions using an instrumental variables approach. This suggests that the previous estimates in the literature that use this approach are likely unbiased and that treatment effects are homogenous in the population. We present supporting evidence that the likely channel for these adverse effects is maternal stress.

Vulnerability and resilience to pandemic-related stress among U.S. women pregnant at the start of the COVID-19 pandemic

RATIONALE

Women pregnant during the COVID-19 pandemic are experiencing moderate to high levels of emotional distress, which has previously been shown to be attributable to two types of pandemic-related pregnancy stress: stress associated with feeling unprepared for birth due to the pandemic (Preparedness Stress) and stress related to fears of perinatal COVID-19 infection (Perinatal Infection Stress).

OBJECTIVE

Given the well-documented harms associated with elevated prenatal stress and the critical importance of developing appropriately targeted interventions, we investigated factors predictive of pandemic-related pregnancy stress.

METHOD

Between April 25 and May 15, 2020, 4,451 pregnant women in the U.S. were recruited via social media to complete an online questionnaire that included sociodemographic, medical, and COVID-19 situational factors, as well as the Pandemic-Related Pregnancy Stress Scale (PREPS). Binary logistic regression was used to calculate odds ratios for high stress.

RESULTS

Nearly 30% of participants reported high Preparedness Stress; a similar proportion reported high Perinatal Infection Stress. Abuse history, chronic illness, income loss due to the pandemic, perceived risk of having had COVID-19, alterations to prenatal appointments, high-risk pregnancy, and being a woman of color were associated with greater levels of one or both types of stress. Access to outdoor space, older age, and engagement in healthy behaviors were protective against stress.

CONCLUSIONS

Practices that may alleviate pandemic-related stress such as minimizing disruptions to prenatal care, ensuring access to outdoor space, and motivating engagement in health behaviors are of vital importance. Particular attention is needed for more vulnerable populations including women of color, women with a history of abuse, and those with high-risk pregnancy. Research focused on the short and longer-term impact of pandemic-related pregnancy stress on maternal mental and physical health, perinatal outcomes, and child development is critical to identify these effects and marshal appropriate resources to reduce them.

Maternal exposure to childhood traumatic events, but not multi-domain psychosocial stressors, predict placental corticotrophin releasing hormone across pregnancy

Maternal psychosocial stress increases the risk of adverse birth and postnatal outcomes for the mother and child, but the role of maternal exposure to childhood traumatic events (CTE) and multi-domain psychosocial stressors for the level and rise of placental Corticotrophin-Releasing Hormone (pCRH) across pregnancy has been understudied. In a sociodemographically and racially diverse sample of 1303 women (64% Black, 36% White/others) with low-medical risk pregnancies at enrollment from Shelby County, Tennessee, USA, blood samples were drawn twice, corresponding roughly to second and third trimester, and extracted prior to conducting radioimmune assays for pCRH. Mothers reported CTE (physical abuse, sexual abuse, or family violence, in childhood), adulthood traumatic events, and interpersonal violence during pregnancy. Neighborhood crime/deprivation was derived using geospatially-linked objective databases. General linear and mixed models tested associations between stress exposure variables and pCRH levels and rate of rise, adjusting for obstetric/clinical/health related factors. Maternal CTE did not predict pCRH levels at time 1, but positively predicted levels at time 2, and the rate of rise in pCRH across pregnancy. Race did not moderate this association. No additional maternal stress exposures across adulthood or during pregnancy predicted pCRH outcomes. Findings indicate that childhood violence or abuse exposure can become biologically embedded in a manner predicting later prenatal physiology relevant for maternal and offspring health, and that such embedding may be specific to childhood, but not adulthood, stress. Findings also highlight the placental-fetal unit as a mechanistic pathway through which intergenerational transmission of the adverse effects of childhood adversities may occur.

Womb at work: The missing impact of maternal employment on newborn health

Parental leave policies across the globe have become much more generous than they used to be. This is also true for prenatal maternal leave. While this may be costly in the short run, little is known about the effect of maternal employment during pregnancy on newborn health. In this paper, I exploit three sharp policy changes on the duration of paid parental leave in Austria that strongly affected the share of mothers who work up to the 32nd week of pregnancy. I use administrative data from Austria on the working history of women linked to the full Austrian birth register and coupled with a regression discontinuity framework to identify the effect of prenatal employment on their offspring. Maternal employment during pregnancy with the second child reacts strongly to these policy changes. The share of employed mothers sharply declined in 1990 by 19.1 percentage points, increased in 1996 by 6.9 percentage points and declined again by 6.4 percentage points in 2000. None of these changes in prenatal employment translated into effects on newborn health measured via birth weight, gestational length, and Apgar scores. This result holds true for mothers of different socioeconomic backgrounds and across industries. The effect is precisely estimated, which suggests that prenatal employment prior to the 32nd week of pregnancy does not causally affect the fetus for measures visible at birth.

In-utero stress and mode of conception: impact on regulation of imprinted genes, fetal development and future health

BACKGROUND

Genomic imprinting is an epigenetic gene regulatory mechanism; disruption of this process during early embryonic development can have major consequences on both fetal and placental development. The periconceptional period and intrauterine life are crucial for determining long-term susceptibility to diseases. Treatments and procedures in assisted reproductive technologies (ART) and adverse in-utero environments may modify the methylation levels of genomic imprinting regions, including insulin-like growth factor 2 (IGF2)/H19, mesoderm-specific transcript (MEST), and paternally expressed gene 10 (PEG10), affecting the development of the fetus. ART, maternal psychological stress, and gestational exposures to chemicals are common stressors suspected to alter global epigenetic patterns including imprinted genes.

OBJECTIVE AND RATIONALE

Our objective is to highlight the effect of conception mode and maternal psychological stress on fetal development. Specifically, we monitor fetal programming, regulation of imprinted genes, fetal growth, and long-term disease risk, using the imprinted genes IGF2/H19, MEST, and PEG10 as examples. The possible role of environmental chemicals in genomic imprinting is also discussed.

SEARCH METHODS

A PubMed search of articles published mostly from 2005 to 2019 was conducted using search terms IGF2/H19, MEST, PEG10, imprinted genes, DNA methylation, gene expression, and imprinting disorders (IDs). Studies focusing on maternal prenatal stress, psychological well-being, environmental chemicals, ART, and placental/fetal development were evaluated and included in this review.

OUTCOMES

IGF2/H19, MEST, and PEG10 imprinted genes have a broad developmental effect on fetal growth and birth weight variation. Their disruption is linked to pregnancy complications, metabolic disorders, cognitive impairment, and cancer. Adverse early environment has a major impact on the developing fetus, affecting mostly growth, the structure, and subsequent function of the hypothalamic-pituitary-adrenal axis and neurodevelopment. Extensive evidence suggests that the gestational environment has an impact on epigenetic patterns including imprinting, which can lead to adverse long-term outcomes in the offspring. Environmental stressors such as maternal prenatal psychological stress have been found to associate with altered DNA methylation patterns in placenta and to affect fetal development. Studies conducted during the past decades have suggested that ART pregnancies are at a higher risk for a number of complications such as birth defects and IDs. ART procedures involve multiple steps that are conducted during critical windows for imprinting establishment and maintenance, necessitating long-term evaluation of children conceived through ART. Exposure to environmental chemicals can affect placental imprinting and fetal growth both in humans and in experimental animals. Therefore, their role in imprinting should be better elucidated, considering the ubiquitous exposure to these chemicals.

WIDER IMPLICATIONS

Dysregulation of imprinted genes is a plausible mechanism linking stressors such as maternal psychological stress, conception using ART, and chemical exposures with fetal growth. It is expected that a greater understanding of the role of imprinted genes and their regulation in fetal development will provide insights for clinical prevention and management of growth and IDs. In a broader context, evidence connecting impaired imprinted gene function to common diseases such as cancer is increasing. This implies early regulation of imprinting may enable control of long-term human health, reducing the burden of disease in the population in years to come.

The Embodiment of War: Growth, Development, and Armed Conflict

Armed conflict regularly presents extremely adverse circumstances not only for combatants, but also for civilians. In fact, estimates from various wars over the past 70 years suggest that noncombatants comprise the majority of casualties. For survivors, war's effects are often embodied, leaving long-term effects on health and biology. Some of these effects, such as injuries and psychological trauma, are well known. Yet other effects may be subtle and may be elucidated by a developmental biological perspective. In early life, when growth rates are highest, conditions of war may have their greatest impact. Depending on local circumstances, a developing embryo, infant, or child growing in a place embroiled in armed conflict is likely to face—directly or indirectly—various stressors, including malnutrition, infectious disease, and/or psychological stress. Thus, the conditions of war and forced displacement may become embodied, getting under the skin for fundamental biological reasons.

Gender inequality, economic growth, and the intergenerational transmission of adverse health consequences at birth

We estimate a gender differential in the intergenerational transmission of adverse birth outcomes. We link Taiwan birth certificates from 1978 to 2006 to create a sample of children born in the period 1999-2006 that includes information about their parents and their maternal grandmothers. We use maternal-sibling fixed effects to control for unobserved family-linked factors that may be correlated with birth outcomes across generations, and define adverse birth outcomes as small for gestational age. We find that when a mother is in the 5th percentile of birth weight for her gestational age, then her female children are 49-53% more likely to experience the same adverse birth outcome compared to other female children, while her male children are 27-32% more likely to experience this relative to other male children. We then investigate whether long-run improvements in local socio-economic conditions experienced by the child's family, as measured by intergenerational changes in town-level maternal education, affect the gender differential. We find no evidence that intergenerational improvements in socioeconomic conditions reduce the gender differential.