Prenatal per- and polyfluoroalkyl substances exposure and child neurodevelopment from birth to age 7: A prospective study in the Laizhou Wan Birth Cohort.

Per- and polyfluoroalkyl substances (PFAS) are persistent environmental contaminants; however, their long-term neurodevelopmental effects following prenatal exposure remain incompletely characterized. This study examined associations between prenatal PFAS exposure and longitudinal neurodevelopment from birth to age 7 years old, with attention to sex-specific effects and thyroid hormone-mediated pathways. Using data from the Laizhou Wan Birth Cohort, 221 mother-infant pairs with at least three neurodevelopmental assessments were included. PFAS concentrations were quantified in cord blood at delivery, and neurodevelopment was evaluated using validated instruments. Generalized Linear Mixed-Effects Models and Bayesian Kernel Machine Regression were applied. Prenatal exposure to perfluorohexanesulfonic acid (PFHxS) (OR = 3.76, 95% CI: 1.10-11.24) and perfluorooctanoic acid (PFOA) (OR = 2.15, 95% CI: 1.01-4.62) was associated with below-average neurodevelopment. Female offspring showed greater sensitivity to PFHxS exposure (OR = 6.73, 95% CI: 1.19-38.19). Mediation analyses indicated that thyroid hormone disruption may partially mediate these associations, with stronger effects observed in females. Associations were most evident at ages 1-2 years. These findings suggest that prenatal PFAS exposure is associated with adverse neurodevelopmental outcomes and highlight thyroid hormone disruption and sex-specific susceptibility during early childhood.