Prenatal microplastic exposure and umbilical cord blood androgenic and glucocorticoid hormones

Placental microplastic exposure has emerged as a potential environmental risk factor affecting fetal development. This study investigates the association between placental microplastic burden and umbilical cord hormone levels in a cohort of pregnant women from Shenyang, China. A total of 1324 pregnant women during 2022-2023 were enrolled. Placental microplastics were quantified using a laser direct infrared (LD-IR) chemical imaging system, targeting polyvinyl chloride (PVC), polypropylene (PP), and polybutylene succinate (PBS). Umbilical cord blood cortisol, cortisone, dehydroepiandrosterone (DHEA), and androstenedione were analyzed using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Regression models were applied to assess individual microplastic associations, while quantile-based g-computation (g-comp) and Bayesian Kernel Machine Regression (BKMR) were used to evaluate mixture effects. Microplastics were detected in all placental samples, with a median total concentration of 12 particles/10 g. Placental microplastic exposure was significantly associated with altered fetal hormone levels. Higher PVC, PBS, and total microplastic concentrations were linked to lower cortisol levels, while PVC, PP, and total microplastics were associated with reduced cortisone. In contrast, PBS and total microplastics were positively associated with DHEA, and PVC, PBS, and total microplastics correlated with increased androstenedione. The cortisol/DHEA and glucocorticoid/androgenic ratios were significantly reduced with higher microplastic exposure, suggesting endocrine disruption. Mixture analysis confirmed these trends, showing decreased glucocorticoids and increased androgens, with sex-stratified analysis indicating stronger cortisol reductions in boys and higher DHEA in girls. Overall, placental microplastic exposure was associated with altered fetal hormone levels, suggesting potential endocrine disruption while further studies are needed.