Higher Urinary Bisphenol A Concentration Is Associated with Unexplained Recurrent Miscarriage Risk: Evidence from a Case-Control Study in Eastern China

BACKGROUND Evidence about the association between Bisphenol A (BPA) and the risk of recurrent miscarriage (RM) in human being is still limited. OBJECTIVE We evaluated the association of urinary BPA concentrations with RM in human being. METHODS A hospital-based 1:2 matched case-control study on RM was carried out in Suzhou and Kunshan in Jiangsu Province in China between August 2008 and November 2011. Total urinary BPA concentrations in 264 eligible urine samples (102 RM patients and 162 controls) were measured using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The Wilcoxon test and conditional logistic regression were used to estimate the differences between the groups and odds ratios (OR) with 95% confidence intervals (CI), respectively. RESULTS The median ± IQR (interquartile range) (P75-P25) values of non-creatinine-adjusted total urinary BPA levels in the RM patients and the controls were 1.66 ± 3.69 ng/ml and 0.58 ± 1.07 ng/ml, respectively (0.98 ± 2.67 μg/g Cr (creatinine) and 0.40 ± 0.77 μg/g Cr. The adjusted BPA level was significantly higher in the RM patients than in the controls (Wilcoxon test, Z = 4.476, P < 0.001). Higher level of urinary BPA was significantly associated with an increased risk of RM (P-trend < 0.001). Compared to the groups with urinary BPA levels less than 0.16 μg/g Cr, the women with levels of 0.40-0.93 μg/g Cr and 0.93 μg/g Cr or above had a significantly higher risk of RM (OR = 3.91, 95%CI: 1.23-12.45 and OR = 9.34, 95%CI: 3.06-28.44) that persisted after adjusting for confounding factors. The time from recently RM date to recruitment does not significantly influence the urinary BPA level (P = 0.090). CONCLUSION Exposure to BPA may be associated with RM risk.