Maternal serum bisphenol A levels and risk of pre-eclampsia: a nested case–control study

Background Although recent studies have indicated the potential adverse effects of maternal bisphenol A (BPA) exposure on pregnancy such as increasing the risk of pre-eclampsia, epidemiological evidence is limited. We aimed to evaluate the relationship between maternal BPA exposure and the risk of pre-eclampsia. Methods We conducted a nested case-control study among 173 women (74 cases of pre-eclampsia and 99 controls). BPA concentrations were measured using liquid chromatography-mass spectrometry in the maternal serum samples collected during 16-20 gestational weeks. Multivariate logistic models were used to examine the relationship between maternal serum BPA concentrations and the risk of pre-eclampsia. Results BPA was detectable (>0.1 µg/l) in 78.6% of the maternal serum samples at three levels: low (<2.24 µg/l), medium (2.24-4.44 µg/l), and high (>4.44 µg/l). BPA concentrations were significantly higher in the serum samples collected from the pre-eclampsia cases than those from controls (median: 3.40 vs. 1.50 µg/l, P < 0.01). With adjustment for maternal age, primiparous and BMI, the odds of developing pre-eclampsia were significantly elevated in subjects with high serum BPA levels compared with those with low levels (adjusted OR = 16.46, 95%CI = 5.42-49.85) regardless of subcategories of pre-eclampsia including severity and onset time. Among the pre-eclampsia subjects, the maternal serum concentration of BPA was not different between the early- and late-onset subjects (median: 3.09 vs. 3.50 µg/l, P = 0.57), but surprisingly higher in mild pre-eclampsia subjects compared with severe pre-eclampsia subjects (median: 5.20 vs. 1.80 µg/l, P < 0.01). Conclusions These results demonstrated that maternal exposure to high level of BPA could be associated with an increased risk of pre-eclampsia.