Free bisphenol A (BPA), BPA-Glucuronide (BPA-G), and total BPA concentrations in maternal serum and urine during pregnancy and umbilical cord blood at delivery

Abstract

While adult exposure to total bisphenol A (BPA) has been well documented, developmental exposure to BPA and fetal exposure to the bioactive form (free BPA) remains poorly defined. Therefore, pregnant women (n = 199) between 28 and 35 weeks of pregnancy were invited to participate in this study. Maternal serum free of hemolysis (n = 189) and urine (n = 112) were collected at third trimester and delivery along with umbilical cord blood (UCB) at delivery. Free BPA, BPA mono-glucuronide (BPA-G) and total BPA concentrations were measured using gas chromatography coupled with tandem mass spectrometry. Circulating concentrations of free BPA were quantifiable above the method detection limit (MDL = 0.026 ng/mL) in approximately 34% of serum samples in the third trimester and 21% of samples at delivery whereas BPA-G and total BPA were quantified in 43 and 70% of third trimester and delivery samples, respectively. The geometric mean of free BPA, BPA-G and total BPA concentrations in maternal serum during the third trimester and at delivery were 0.62 ng/L and <MDL, 0.09 and 0.28 ng/mL, and 0.24 and 0.31 ng/mL, respectively. Geometric mean urinary concentrations of free BPA, BPA-G, and total BPA (MDL = 0.027 ng/mL) in the third trimester and delivery samples were 0.07 and 0.06 ng/mL, 0.36 and 0.09 ng/mL, and 0.36 and 0.09 ng/mL, respectively. In the UCB, the geometric means for free BPA, BPA-G, and total BPA concentrations were 0.05, 0.08 and 0.10 ng/mL, respectively. Our results suggest that, in our study population, free BPA concentrations were low compared to other Canadian cohorts. Keywords: Bisphenol A, Free BPA, Conjugated BPA, Pregnancy, Exposure, Fetal development, Cord blood