Association between particulate air pollution exposure during pregnancy and postpartum maternal psychological functioning

Abstract

Methods: We studied associations between prenatal exposure to particulate matter with diameter ≤ 2.5 μm (PM2.5) and postpartum psychological functioning in a lower income, ethnically mixed sample of urban US women enrolled in a pregnancy cohort study. Analyses included 557 mothers who delivered at ≥37 weeks gestation. Daily estimates of residential PM2.5 over gestation were derived using a satellite-based spatio-temporally resolved model. Outcomes included the Edinburgh Postnatal Depression Scale (EPDS) score from 6 or 12 months postpartum and subscale scores for anhedonia, depressive and anxiety symptoms. Associations were also examined within racial/ethnic groups. Distributed lag models (DLMs) were implemented to identify windows of vulnerability during pregnancy.

Results: Most mothers had less than a high school education (64%) and were primarily Hispanic (55%) and Black (29%). In the overall sample, a DLM adjusted for age, race, education, prenatal smoking, and season of delivery, we found significant associations between higher PM2.5 exposure in the second trimester and increased anhedonia subscale scores postpartum. In race stratified analyses, mid-pregnancy PM2.5 exposure was significantly associated with increased total EPDS scores as well as higher anhedonia and depressive symptom subscale scores among Black women.

Conclusions: Increased PM2.5 exposure in mid-pregnancy was associated with increased depressive and anhedonia symptoms, particularly in Black women.

Fig 1. Association between weekly PM_2.5 exposure and EPDS scores (total score and anhedonia, anxiety and depressive symptom subscales).

This figure demonstrates the association between weekly averaged PM_2.5 during pregnancy and postpartum EPDS total and subscale scores using a distributed lag model assuming week-specific effects, adjusting for race, education, age, prenatal smoking status and season of delivery. The y-axis shows the change in EPDS score in relation to a 10 μg/m3 increase in PM_2.5 level; the x-axis depicts gestational weeks of the pregnancy. The solid line shows the predicted change, and the gray area indicates the 95% confidence interval. A sensitive window is identified when the estimated pointwise 95% confidence interval does not include 0.

Fig 2. Association between weekly PM_2.5 exposure and EPDS scores (total score and anhedonia, anxiety and depressive symptom subscales) stratified by race/ethnicity.

Within each stratum, this figure demonstrates the association between PM_2.5 exposure during pregnancy and postpartum EPDS total and subscale scores using a distributed lag model assuming week-specific effects, adjusting for education, age, prenatal smoking status and season of delivery. The y-axis shows the change in EPDS score in relation to a 10 μg/m3 increase in PM_2.5 level; the x-axis depicts gestational weeks of the pregnancy. The solid line shows the predicted score change, and the gray area indicates the 95% confidence interval. A sensitive window is identified when the estimated pointwise 95% confidence interval does not include 0.