Health Risks of Transplacental Exposure to Endocrine Disruptors

Abstract

Prenatal exposures to environmental toxicants may influence fetal development and children's health later in life. The placenta is a critical reproductive organ that regulates fetal nutrient supply and protects the fetus from environmental perturbations. Transplacental exposures are important due to their direct contact with the fetal circulation. Exposure assessment and epidemiology studies can assess transplacental exposures by measuring toxicants in several tissues, including placental tissue, amniotic fluid, cord blood, and samples from newborns (e.g. nail clippings and hair). This chapter reviews epidemiological studies of transplacental exposures to endocrine disrupting toxicants in association with child health outcomes. This review reports findings from studies that provide evidence of increased risk for adverse birth outcomes, child metabolic disorders, neurodevelopmental outcomes, and reproductive disorders in association with transplacental exposures to several toxicant classes. However, we also discuss studies that reported either null findings or protective associations for health effects related to transplacental exposures. The differences in reported associations may be a function of multiple factors, including differences in exposure distribution across populations, exposure assessment techniques, and temporal nuances in metabolism of toxicant classes. The major gap in this literature is the evaluation of joint associations of toxicant mixtures wherein the health effects of a given toxicant may be influenced by co-exposures to other toxicants. Future studies should incorporate comprehensive mixtures analyses to better characterize the effects of transplacental exposures to endocrine disrupting toxicants.