Relationship between Polybrominated Diphenyl Ether (PBDE) Levels in Maternal Serum and Fetal Tissues during Mid-Gestation of Pregnancy and Associations with Placental Biomarkers of Growth and Development

Abstract

Polybrominated diphenyl ether (PBDE) compounds are flame retardant chemicals with adverse effects on brain development, which may be mediated by placental effects. Pharmacokinetic factors may lead to disproportionate exposure in the developing fetus, yet the maternal-fetal relationship is not well understood. We examined whether PBDE concentrations vary between mother and fetus during early-to-mid pregnancy and identified placental biomarkers of PBDE exposure that may influence placental growth and function using statistical methods that account for left censored PBDE data. We calculated correlations between levels of 19 PBDE congeners across three biological matrices (maternal serum, placenta tissue, and fetal liver) in 130 maternal-fetal units. We conducted an exploratory analysis in a subset of samples to identify biomarkers of PBDE exposures that may influence placental development and function. Detection frequency was highest for BDE-47 (> 93% across matrices). Congener BDE-28 was more highly detected in placental and fetal liver tissues than maternal serum (> 60% compared to < 20%). PBDE levels were similar or higher in maternal compared to placental and fetal tissues before and after lipid adjustment for most congeners. The median BDE-47 concentration in serum was 0.24 ng/g (95% CI: 0.22, 0.28), more than twice as high as the placental value of 0.10 ng/g (95% CI: 0.09, 0.12). The difference was more pronounced after lipid adjustment, with 35.5 ng/g lipid BDE-47 found in serum compared to 10.8 ng/g in the placenta. Lipid-adjusted BDE-28, -99, and -153 levels were ~ two times higher in the placenta and fetal liver. Biomarker changes were observed in a subset of 12 placental tissues. Prenatal PBDE exposures are correlated with maternal levels. Molecular biomarkers related to placental development and function may be informative measures of PBDE exposure in future studies.