Serum levels of perfluoroalkyl acids in mothers and infants: transplacental and lactational transfer from the mother

Abstract

Objectives: The aim of the present study is to investigate the impact of pregnancy and breast-feeding on maternal and infant serum PFAA concentrations among residents of the mid-Ohio Valley. Women were exposed to PFOA from industrial emissions and participated in the C8 Study in 2005-6, which included serum measurements of PFOA. Methods: We compared serum PFOA concentrations of 404 women who were pregnant at survey, adjusted for age, water district and parity, with 4484 women of similar age range (18-35) not pregnant within 3.5 years. For 633 women who had given birth within 42 months of the survey along with 8%(n=49) of the infants, we regressed serum PFOA concentrations on reported duration of breast-feeding compared to the non breast feeders, adjusting for maternal and child age and water district. Results: Attributable to pregnancy, we observed decreases in serum PFOA in pregnant compared to non-pregnant women: 19% decrease (95%CI: 5%, 30%) for the first trimester and 23% (11%, 33%) for the third. For PFOS, decreases were not statistically significant. Due to lactation, we observed 34% (23%, 44%) and 26% (16%, 34%) decreases in maternal PFOA and PFOS levels, respectively, per 12 months breastfeeding and a stronger decreased effect of 60% (27%, 78%) for women with past, but not on-going, exposure to PFOA above background level. For infants, serum levels in bottle-fed infants were similar to their mothers, but breastfeeding increased children’s serum PFOA concentrations 2.0-fold (1.0, 3.0) and for PFOS 2.2-fold (1.4, 3.4). Conclusions: This study suggests that pregnancy and lactation significantly impact serum levels of PFAAs and in utero and lactational transfer are important exposure routes to infants. Further, breastfeeding practice and duration should be considered when estimating in utero levels from serum measurements taken postnatally.