Personal care product use and per- and polyfluoroalkyl substances in pregnant and lactating people in the Maternal-Infant Research on Environmental Chemicals study

Background: Per- and polyfluoroalkyl substances (PFAS) are ubiquitous chemicals routinely detected in personal care products (PCPs). However, few studies have evaluated the impact of PCP use on PFAS concentrations in pregnant and lactating populations. Objective: We investigated associations between PCP use and PFAS concentrations in prenatal plasma and human milk. Methods: We leveraged the Maternal-Infant Research on Environmental Chemicals (MIREC) Study to evaluate the contribution of PCP use on PFAS concentrations in prenatal plasma (6 to 13 weeks’ gestation; n = 1,940) and human-milk (2 to 10 weeks’ postpartum; n = 664). Participants reported frequency of use across 8 PCP categories during the 1st and 3rd trimesters, 1 to 2 days postpartum, and 2 to 10 weeks’ postpartum. We used adjusted linear regression models to quantify percent differences and corresponding 95 % confidence intervals. Results: In 1st trimester pregnant people, we found higher use of nailcare products (≥once a week vs. never: perfluorooctanoic acid (PFOA): 21 % [9.7 %, 32 %]; perfluorooctane-sulfonic acid (PFOS): 11 % [0.3 %, 23 %]), fragrances (daily vs. never: PFOA: 14 % [7.8 %, 21 %]; PFOS: 7.8 % [1.3 %, 15 %]), makeup (daily vs. never: PFOA: 14 % [5.8 %, 23 %]), hair dyes (never vs. 1-2 times during pregnancy: PFOA: 8.3 % [2.4 %, 15 %]), and hair sprays or gels (daily vs. never: PFOA: 12 % [5.0 %, 19 %], PFOS: 7.1 % [0.2 %, 15 %]) were associated with higher plasma PFAS concentrations. Similar results were observed for 3rd trimester PCP use and 2 to 10 weeks’ postpartum human-milk PFAS concentrations. In addition, we also found that people using colored-permanent dye 1 to 2 days postpartum had higher Sm-PFOS (18 % [2.7 %, 35 %]), PFOA (16 % [4.3 %, 29 %]), and perfluorononanoic acid (17 % [3.6 %, 33 %]) postpartum human-milk concentrations. Conclusions: Our results show that PCP use may be a modifiable source of PFAS exposure in pregnant and lactating populations. These results along with growing scientific evidence can help inform PFAS regulation and guide individual choices to reduce PFAS exposure.