In utero exposure to per- and polyfluoroalkyl substances and neonatal sex hormone levels: Implications of endocrine disrupting effects during critical development windows

Emerging evidence indicates that prenatal exposure to per - and polyfluoroalkyl substances (PFASs) may adversely affect endocrine function, particularly during critical windows of fetal development. This study evaluated the impact of prenatal PFAS exposure on neonatal sex hormone levels—total testosterone, estradiol, prolactin, and progesterone—in a cohort of newborns from Beijing, China. We quantified 19 individual PFAS compounds and examined their individual and combined effects on neonatal hormone levels using linear regression, restricted cubic spline (RCS) analysis, weighted quantile sum (WQS) regression, and Bayesian benchmark dose (BMD) modeling. Our results revealed significant positive associations between increased exposure to PFOA (β = 0.115, 95 % CI: 0.050–0.180) and total PFAS (β = 0.066, 95 % CI: 0.010–0.122) and elevated testosterone levels. Additionally, PFUdA exposure was positively associated with increased prolactin levels (β = 0.149, 95 % CI: 0.021–0.277). The RCS analysis further demonstrated non-linear dose-response associations for PFOA and total PFAS exposure with testosterone levels. WQS regression indicated significant positive associations between PFAS mixtures and both testosterone ( P = 0.0014) and prolactin ( P = 0.0208), with PFOA, PFUdA, and 6: 2 Cl-PFESA identified as predominant contributors to these hormonal disruptions. Stratified analyses highlighted notable sex-specific modification effects, with significant interactions observed for PFHxS, PFTeDA, and PFOA influencing testosterone levels, and PFHxS affecting progesterone and prolactin (P for interaction <0.05). Bayesian benchmark dose (BMD) analysis yielded exposure threshold estimates, identifying BMD₁₀ values of 3.72 ng/mL for PFOA and 2.32 ng/mL for PFUdA associated with a 10 % increase in testosterone and prolactin levels, respectively. Furthermore, we integrated toxicogenomics analysis by identifying candidate genes for PFAS and sex hormones using the Comparative Toxicogenomics Database (CTD) and GeneCards databases. The core targets were subsequently confirmed through STRING analysis and visualized with Cytoscape software. To explore potential molecular mechanisms underlying the endocrine-disrupting effects of PFAS, we performed enrichment analyses of these core targets using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases. Collectively, these findings suggest that prenatal PFAS exposure may disrupt neonatal hormone homeostasis, especially affecting testosterone and prolactin, with distinct sex-specific effects. This study underscores the urgent need for further research into the underlying mechanisms of PFAS-mediated endocrine disruption and highlights the importance of developing public health strategies to minimize prenatal PFAS exposure, thereby protecting fetal development. • PFAS prenatal exposure was linked to higher neonatal testosterone and prolactin. • PFOA and PFUdA were key contributors in both single and mixture exposure models. • Sex-specific effects revealed fetal sex modifies PFAS–hormone associations. • BMD modeling identified exposure thresholds for hormone-disrupting PFAS levels. • Toxicogenomics revealed shared targets and pathways for PFAS hormonal effects.