Maternal Urinary Benzophenone-3 Concentrations During Pregnancy and Duration of Breastfeeding

Abstract

Background: Benzophenone-3, an ultraviolet-protectant used in some sunscreens and personal care products, is detectable in the urine of virtually all Americans. In animal models, gestational benzophenone-3 exposure leads to alterations in mammary gland morphology and function. However, it is unknown if benzophenone-3 exposure affects mammary gland function in humans. We estimated the association between maternal urinary benzophenone-3 concentrations during gestation and subsequent breastfeeding duration. Methods: We used data from 302 mother-child pairs in the HOME Study (Cincinnati, Ohio, enrolled: 2003-2006). We calculated average benzophenone-3 concentrations in two urine samples collected from women at 16- and 26-weeks gestation. After delivery, participants completed standardized interviewer-administered surveys on their breastfeeding practices every 3 months until discontinuation of breastfeeding or when children were age 3 years. We used a multivariable Poisson regression model with robust standard errors adjusted for relevant demographic and perinatal potential confounders to estimate the relative risk (RR) of discontinuing breastfeeding by age 3 months or 6 months with increasing benzophenone-3 concentrations.Results: Median urinary benzophenone-3 concentrations were 35 ng/mL (25th-75th percentile: 11-107). Approximately 57% and 44% of women fed their infants some breastmilk until 3 and 6 months, respectively. Increasing urinary benzophenone-3 concentrations were not associated with a higher risk of breastfeeding cessation at 3 months (RR for 3rd vs. 1st tercile=1.09; 95% CI: 0.75-1.58) or at 6 months (RR for 3rd vs. 1st tercile=1.13; 95% CI: 0.86-1.21).Conclusion: In this cohort, gestational urinary benzophenone-3 concentrations were not associated with duration of breastfeeding.