Purpose: The present report describes the distribution of breast milk and urinary free and total bisphenol A (BPA) concentrations, from 27 postpartum women and their 31 infants, and explores the influence of age, sex, and nutritional source on infant BPA urinary concentration.
Methods: Both free (unconjugated) and total (free plus conjugated) BPA concentrations from women's breast milk samples and infants' urine samples were measured by online solid-phase extraction coupled to high-performance liquid chromatography-isotope dilution tandem mass spectrometry. Descriptive statistics and nonparametric tests of group comparisons were conducted.
Results: Total BPA was detected in 93 % of urine samples in this healthy infant population aged 3-15 months who were without known environmental exposure to BPA [interquartile range (IQR) = 1.2-4.4 μg/L)]. Similarly, 75 % of the mothers' breast milk samples had detectable concentrations of total BPA (IQR = 0.4-1.4 μg/L). The magnitude and frequency of detection of free BPA in the children's urine and the mothers' breast milk were much lower than the total concentrations.
Conclusions: Total BPA was detected in 93 % of this healthy infant population aged 3-15 months who are without known environmental exposure to BPA. Neither free nor total BPA urinary concentrations differed significantly by infant's sex or by nutritional source (breast milk and/or formula) while age group was of borderline significance. There were no significant correlations between free or total BPA concentrations in mothers' breast milk and their infants' urine.