Occurrence and Maternal Transfer of Chlorinated Bisphenol A and Nonylphenol in Pregnant Women and Their Matching Embryos

Abstract

Prenatal exposure has recently raised concerns over the health risks of endocrine disruptors; however, little is known about their extent and the mechanisms of maternal transfer in the embryo stage. In this study, bisphenol A (BPA), nonylphenol (NP), and their six chlorinated derivatives were quantified in decidua samples from 25 pregnant women and their matching embryos, which were collected as chorionic villi samples. Monochloro-BPA (MCBPA), dichloro-BPA (DCBPA), monochloro-NP (MCNP), and dichloro-NP (DCNP) were detected in over 70% of the decidua or chorionic villi samples, while BPA, NP, trichloro-BPA (TCBPA), and tetrachloro-BPA (TeCBPA) were detected in less than half. The geometric mean (GM) concentrations of MCBPA, DCBPA, NP, MCNP, and DCNP in chorionic villi samples were 0.13, 0.17, 5.33, 4.52, and 2.44 ng/g dw, respectively, higher than those in maternal decidua samples, which were 0.10, 0.12, 3.27, 1.85, and 0.74 ng/g dw, respectively, while the GM concentration of BPA was lower in chorionic villi samples (0.09 ng/g dw) than in maternal decidua (0.10 ng/g dw). The ratios of the average lipid-normalized concentrations of chemicals in chorionic villi to those in maternal decidua (EMR) were calculated to be 1.53 for MCNP and 2.38 for DCNP, while those of BPA, MCBPA, DCBPA, and NP were lower than 1 (0.39-0.97). Such obvious difference in maternal transfer is probably due to their different affinities to plasma proteins, as exemplified by the correlation between EMR and the binding affinities to T4 transport proteins (TTR). This is the first report on the occurrence and maternal transfer of chlorinated derivatives of BPA and NP in human embryos and decidua.