Prenatal low-level phenol exposures and birth outcomes in China

Phenolic compounds are among the endocrine disruptors which are widely used in daily life products. Studies in laboratory animals showed reproductive and developmental effects. In spite of widespread exposure to phenols, only few studies examined their effects on human development. This study was designed to investigate the relationship between antenatal phenol exposure and birth outcomes in a Chinese obstetric population. Four hundred ninety-six mother-infant pairs recruited from the Laizhou Wan prospective birth cohort in northern China between 2010 and 2013 were included in the study. We measured two phenol metabolites in maternal urine at delivery and examined their associations with birth outcomes including birth weight, crown-heel length, head circumference, gestational age, and ponderal index. Median levels of bisphenol A (BPA) and triclosan (TCS) in urine were 1.07 and 0.50μg/g creatinine, respectively. After adjusting for confounders, a 10-fold increase in BPA levels was associated with a 0.63cm [95% confidence interval (CI): 0.25 to 1.01] increase in birth length among boys, but not among girls. No associations were found between TCS levels and any birth outcomes. The positive association of prenatal low-level BPA exposures with anthropometric measures observed among boys, suggests gender differences in the response to antenatal phenol exposure. Given the variability in urinary phenol levels reported during pregnancy, our findings based on levels of the target biomarkers in a single urine sample need to be confirmed in additional studies.