Maternal transfer of bisphenol analogues and their conjugated metabolites.

Human prenatal exposure to bisphenol analogues (BPs) and their conjugated BP metabolites may pose risks to fetal development. However, studies comprehensively investigating the transplacental transfer of BPs and their conjugated metabolites remain limited. This study provides the most comprehensive investigation on presence, transplacental transfer efficiencies, and potential influence of placental transporters for 12 BPs and 14 conjugated BP metabolites in maternal and cord plasma samples (147 pairs) from Chinese participants. Bisphenol A (BPA) and bisphenol SIP (BPSIP) were consistently detected as the most abundant BPs in maternal (mean 0.98 ng/mL and 0.59 ng/mL, respectively) and cord plasma (mean 0.92 ng/mL and 0.66 ng/mL, respectively). BPA-glucuronide (BPA-G) and bisphenol AF-sulfate (BPAF-S) were the predominant conjugated BP metabolites identified in maternal (mean 0.71 ng/mL and 0.66 ng/mL, respectively) and cord plasma (mean 0.71 ng/mL and 0.73 ng/mL, respectively) samples. Among BPs, BPAP (mean 1.2) showed the highest mean transplacental transfer efficiency (TTE) value, followed by BPSIP (1.1), bisphenol F (1.1), and BPA (0.94). Among conjugated BP metabolites, BPAF-G (mean 1.7) exhibited the highest mean TTE, which was followed by BPS-G (1.2) and BPA-G (1.1). Transcript levels of placental transporters ABCA1 and ABCB1 were negatively (p < 0.05) correlated with the TTE of bisphenol M. The transcript levels of solute carrier SLCO2B1 and SLC22A4 were positively (p < 0.05) correlated with the TTE of BPAP. This study advances our understanding of the knowledge on the transplacental transfer behaviors for BPs and their conjugated metabolites, while elucidating the roles of transplacental transporters in modulating fetal exposure.