Disentangling Associations Among Maternal Lifetime and Prenatal Stress, Psychological Functioning During Pregnancy, Maternal Race/Ethnicity, and Infant Negative Affectivity at Age 6 Months: A Mixtures Approach.

Rebecca K Campbell,Kelly J Brunst,Michelle Bosquet Enlow,Paul Curtin,Rosalind J Wright,Robert O Wright

doi:10.1089/heq.2020.0032

Abstract

Purpose: Maternal stress and psychological dysfunction in pregnancy are independently linked with fetal neurodevelopment. Stress encompasses environmental stressors and psychological and physiological responses. Stressors and psychopathology co-occur with patterns differing by race/ethnicity. We aimed to extend environmental mixtures methodology to elucidate prenatal stress associations with infant negative affectivity (NA) in a racially/ethnically mixed cohort.Methods: Participants were mother/infant dyads (n=445) in a prospective pregnancy cohort study in two urban US settings in 2011–2018. During pregnancy, women completed the Life Stressor Checklist-Revised, Crisis in Family Systems-Revised, Edinburgh Postnatal Depression Scale, and post-traumatic stress disorder (PTSD) Checklist-Civilian version; the Infant Behavior Questionnaire-Revised assessed NA in 6-month olds. Using weighted quantile sum (WQS) regression, we developed a weighted maternal stress index encompassing lifetime and current life events and symptoms of depression and PTSD. Stress-by-race/ethnicity interactions allowed differential contributions of individual stress domains by maternal race/ethnicity.Results: Mothers were majority black (44%) or Hispanic (37%). Stress questionnaire and infant NA scores were similar by race/ethnicity. The WQS prenatal stress score was positively associated with infant NA (β: 0.40 [95% confidence interval 0.16–0.64]). PTSD was the strongest contributor to the WQS score in Hispanic women (59%), whereas in black women, lifetime stress and depressive symptoms accounted for 38% and 35%, respectively, of the association with NA.Conclusions: Extending environmental mixtures methodology to stress research may disentangle complex associations among lifetime and current stressful life events and psychological symptomatology and their contributions to early childhood neurobehavioral outcomes. Consideration of effect modification by race/ethnicity may inform understanding of differing vulnerability across racial/ethnic groups.

Highlights

Using weighted quantile sum (WQS) regression, we developed a weighted maternal stress index encompassing lifetime and current life events and symptoms of depression and post-traumatic stress disorder (PTSD)
We found that maternal lifetime stress, NLEs, and symptoms of depression and PTSD, each considered in separate models, were positively associated with infant negative affectivity (NA)
In this diverse urban sample, we found that the individual contribution of each stress component of the mixture was different when conditioned on maternal race/ethnicity

Summary

Introduction

Maternal prenatal stress is a complex phenomenon encompassing the environmental stressors that women experience as well as their consequent psychological and physiological responses, which in turn can influence fetal neurodevelopment.[1,2] In addition to stress experienced during pregnancy, chronic adversity and traumatic stressors experienced over the mother’s lifetime are important to understanding effects on child health.[3,4,5] Studies that include multiple measures of stress (traumatic and nontraumatic negative life events [NLEs], current vs. remote events, distress symptoms) considered one at a time show differential impacts of these various aspects of maternal prenatal stress on child behavioral outcomes.[1,6,7]While the prevalence of neurobehavioral disorders has not been widely studied in socioeconomically and racially/ethnically diverse samples, there are data showing that black and Hispanic populations in the United States may be disproportionately burdened.[6,8] Differential exposure to toxic environmental factors may influence these observed disparities. In the United States, cumulative exposure to both traumatic and nontraumatic stressors over a woman’s lifetime differs by race and ethnicity, with minorities experiencing more adverse events compared with white women.[6,9] Racial and ethnic minorities experience unique sources of stress, such as discrimination, chronic financial strain, and higher prevalence of violence in their communities, which may enhance cumulative effects.[10,11,12,13,14,15,16,17] it has been shown that while the psychological sequelae of chronic stress are hypothesized to be biologically based (e.g., related to genetics or disruption of stress response systems such as the hypothalamicpituitary-adrenal axis), they are impacted by experience, including cultural and sociodemographic influences.[18] Research demonstrates that chronic stress may manifest in different psychological symptom profiles across racial/ethnic groups, with documented variations in depressive, anxiety and post-traumatic stress disorder (PTSD) symptoms.[19,20] when examining the types of stressful events as well as the associated psychological sequelae in diverse samples, methods that allow concurrent evaluation of measures across various stress components are needed

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