Transfer of bisphenol A across the human placenta

Objective: The objective of the investigation was to study placental transfer and conjugation of bisphenol A (BPA) across the human placenta. Study Design: Human placentae obtained from healthy term singleton pregnancies were utilized in a dual recirculating model of ex vivo placental perfusion. Seven placentae were perfused with BPA (10 ng/mL) added to the maternal perfusate for 180 minutes. Antipyrine and fluorescein isothiocyanate dextran were used as positive and negative controls, respectively, to validate integrity of the circuits. Concentrations of BPA and its conjugates were determined by liquid chromatography-mass spectrometry. Results: The transfer percentage for antipyrine and BPA were 25.5 ± 1.13% and 27.0 ± 1.88%, respectively, and the transfer index for BPA was 1.1 ± 0.09 after 180 minutes of perfusion. Only 3.2 ± 1.6% of BPA in the fetal compartment was in the conjugated form. Conclusion: Bisphenol A at low environmentally relevant levels can transfer across the human placenta, mainly in active unconjugated form.