Exposure assessment of multiple emerging contaminants in follicular fluid among women undergoing assisted reproduction in China: Variations across regions and seasons.

Emerging contaminants (ECs) may adversely affect female reproductive health, yet their occurrence in follicular fluid remains poorly characterized. In this descriptive study, a validated ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was used to simultaneously quantify 150 ECs across nine groups in 497 follicular fluid samples from women undergoing assisted reproductive technology. About 19 ECs were detected in more than 80% of participants, and phthalates (PAEs) and per- and polyfluoroalkyl substances (PFAS) accounted for 46.0% and 17.6% of the total concentration. Multivariable regression models identified demographic, regional, and clinical factors associated with EC exposure. Higher PFAS concentrations were observed in participants from eastern than central China (all pcor < 0.05). Higher concentrations of eight compounds spanning organophosphate esters, bisphenols, and PAEs were observed among participants whose oocyte retrieval took place in winter, while a paraben and a pyrethroid were higher in summer (all pcor < 0.05). These regional and seasonal patterns may reflect spatial differences in environmental sources and exposure pathways, together with seasonal variation in environmental conditions and human behaviors. These findings provide a basis for future studies to clarify the determinants of contaminant exposure in follicular fluid and its potential relevance to female reproductive health.