Maternal urinary bisphenol A levels and infant low birth weight: A nested case-control study of the Health Baby Cohort in China.

BACKGROUND

Exposure to bisphenol A (BPA), a known endocrine disruptor, has been demonstrated to affect fetal development in animal studies, but findings in human studies have been inconsistent.

OBJECTIVES

We investigated whether maternal exposure to BPA during pregnancy is associated with an increased risk of infant low birth weight (LBW).

METHODS

A total 452 mother-infant pairs (113 LBW cases and 339 matched controls) were selected from the participants enrolled in the prospective Health Baby Cohort (HBC) in Wuhan city, China, during 2012-2014. BPA concentrations were measured in maternal urine samples collected at delivery, and the information of birth outcomes was retrieved from the medical records. A conditional logistic regression was used to evaluate the relationship between urinary BPA levels and LBW.

RESULTS

Mothers with LBW infants had significantly higher urinary BPA levels (median: 4.70μg/L) than the control mothers (median: 2.25μg/L) (p<0.05). Increased risk of LBW was associated with higher maternal urinary levels of BPA [adjusted odds ratio (OR)=3.13 for the medium tertile, 95% confidence interval (CI): 1.21, 8.08; adjusted OR=2.49 for the highest tertile, 95% CI: 0.98, 6.36]. The association was more pronounced among female infants than among male infants, with a statistical evidence of heterogeneity in risk (p=0.03).

CONCLUSIONS

Prenatal exposure to higher levels of BPA may potentially increase the risk of delivering LBW infants, especially for female infants. This is the first case-control study to examine the association in China.