Exposure to environmental stressors is highly prevalent and unequally distributed along socioeconomic lines and may have enduring negative consequences, even when experienced before birth. Yet, estimating the consequences of prenatal stress on children’s outcomes is complicated by the issue of confounding (i.e., unobserved factors correlated with stress exposure and with children’s outcomes). I combine a natural experiment—a strong earthquake in Chile—with a panel survey to capture the effect of prenatal exposure on acute stress and children’s cognitive ability. I find that stress exposure in early pregnancy has no effect on children’s cognition among middle-class families, but it has a strong negative influence among disadvantaged families. I then examine possible pathways accounting for the socioeconomic stratification in the effect of stress, including differential exposure across socioeconomic status, differential sensitivity, and parental responses. Findings suggest that the interaction between prenatal exposures and socioeconomic advantage provides a powerful mechanism for the intergenerational transmission of disadvantage.
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For simplicity, I refer to treatment and control groups based on exposure to the earthquake, although it should be kept in mind that the earthquake is the instrument for prenatal stress.
The influence of small increases in cortisol within a normal range late in the pregnancy is subject to debate, with some studies reporting small negative effects and others reporting small positive effects (Davis and Sandman 2010; Huinzik et al. 2003).
There is also a significant overall difference in cognitive performance between treatment and control areas, captured by the parameter estimate associated with the treatment area. Interviews with local experts suggested that regional differences in quality of preschool and early education institutions may play a role in this baseline difference.
Substantive results remain unaltered if models include a larger set of covariates (Table A2.1 in the online appendix).
I also examined birth weight as a potential mediator of the relationship between stress exposure and children’s cognitive outcomes, finding that it plays no mediating role (online appendix, Table A2.2).
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The author thanks the Departamento de Estudios Sociológicos at Universidad Católica de Chile for implementing the fieldwork. Viviana Salinas provided outstanding assistance managing the project, and Alejandra Abufhele and Daniela Aranis provided exceptional research assistantship. The author also thanks Nicole Marwell, Carolina Milesi, Ricardo Rosas, Matt Salganik, Rachel Sherman, Donald Treiman, and the Demography editors and anonymous reviewers for their helpful comments and suggestions. This study was partially funded by the National Science Foundation (Grant SES 1023841) and the United Nations Development Program UNDP.
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Torche, F. Prenatal Exposure to an Acute Stressor and Children’s Cognitive Outcomes. Demography 55, 1611–1639 (2018). https://doi.org/10.1007/s13524-018-0700-9
- Prenatal stress
- Cognitive ability
- Natural experiment