Exposure to environmental chemicals and perinatal psychopathology

Women are nearly twice as likely to develop mood disorders compared with men, and incidence is greatest during reproductive transitions, including pregnancy and postpartum. Because these periods are characterized by dramatic hormonal and physiologic changes, there is heightened susceptibility to external factors, such as exposure to environmental toxicants, which may play a role in maternal psychopathology. The purpose of this scoping review was to provide an overview of studies conducted in humans and animal models on the effects of nonoccupational exposure to environmental chemicals on maternal psychopathology during the perinatal period. The largest number of studies examined exposure to environmental tobacco smoke and antenatal depression and showed consistently positive findings, although more prospective studies using biomarkers for exposure assessment are needed. The few studies examining persistent organic pollutants such as polybrominated diphenyl ethers and perinatal depression were consistent in showing associations with increased depressive symptoms. Results were mixed for exposure to heavy metals and non-persistent chemicals, but a strong literature in animal models supported an association between bisphenols and phthalates and reduced maternal behavior and care of pups after parturition. Biological mechanisms may include endocrine disruption, neurotransmitter system impairment, alterations in gene expression, and immune activation and inflammation. Additional longitudinal studies that include biospecimen collection are essential to furthering the understanding of how environmental toxicants during pregnancy may affect perinatal psychopathology and the underlying mechanisms of action. Future work should also leverage the parallels between animal and human maternal behavior, thereby highlighting the opportunity for multidisciplinary work in this avenue.