The transfer of per- and polyfluoroalkyl substances (PFAS) from mother to child: Comparison between maternal and cord blood in an Italian cohort

Per- and polyfluoroalkyl substances (PFAS) are persistent synthetic pollutants associated with multisystemic toxicity, including endocrine disruption and developmental risks. While maternal-fetal transmission has been documented, significant gaps remain regarding the fetal burden of emerging and short-chain alternatives. This study quantified 23 PFAS in paired maternal and cord blood samples from 120 women recruited in Italy, between 2024 and 2025 during the ELENA project (Early Life Exposure to per- and polyfluoroalkyl substaNces (PFAS) and HeAlth risks). Analysis was performed using LC-HRMS to evaluate the single and total PFAS burden after solid-phase extraction. PFAS were detected in 99.04% of maternal and 84.8% of cord blood specimens. Legacy compounds, PFOS (99.0%), PFOA (83.7%), and PFHxS (78.8%), were the most prevalent in maternal samples. Significant associations were found between the regular use of processed food and higher levels of maternal 6:2FTS and PFHpS. While the median sums of PFAS in maternal and cord blood were 1.19 ng/mL and 0.49 ng/mL respectively, nearly 30% of women and 3% of cord blood exceeded the 2 ng/mL NASEM threshold associated with potential health risks. In general, when comparing the observation frequencies and concentration of the compounds in paired samples, the kinetic barrier of placenta has been confirmed, with no selective accumulation. The calculated Transplacental Transfer Efficiency (TTE) values suggested that chemical structure significantly dictates fetal burden. These results highlight the urgent need for biomonitoring approaches and targeted strategies to reduce maternal exposure to legacy and emerging PFAS to protect fetal development.