Dominant Pathways of Bisphenol Compound Exposure among Pregnant Women: A Cohort-Based Assessment

Bisphenol A (BPA) and its substitutes are widely detected in human populations, raising concerns about their health impacts, particularly for vulnerable groups such as pregnant women. This study aimed to characterize the internal exposure levels of BPA, bisphenol S (BPS), bisphenol F (BPF), and bisphenol AF (BPAF) among 1,258 pregnant women from the Wuhu Birth Cohort in China and to identify their primary exposure pathways. Serum concentrations were determined using ultra-high-performance liquid chromatography–tandem mass spectrometry (UHPLC–MS/MS). Mixed exposure to bisphenols was prevalent, with detection rates of 100% for BPS, 98.9% for BPAF, 84.0% for BPF, and 85.1% for BPA. BPA showed the highest median concentration (238.8 ng/g). Correlation and regression analyses consistently identified dietary intake as the dominant exposure route. Consumption of pork (adjusted odds ratio [aOR] = 2.806, 95% CI: 2.031–3.877) and poultry (aOR = 1.755, 95% CI: 1.064–2.895) was significantly associated with elevated BPA exposure risk. Egg intake was related to higher BPS exposure (aOR = 1.517, 95% CI: 1.058–2.174), while wheat product consumption was linked to higher BPF exposure (aOR = 1.524, 95% CI: 1.123–2.070). Dermal contact and inhalation pathways did not show consistent associations with serum bisphenol levels. The results demonstrate widespread co-exposure to BPA and its substitutes in Chinese pregnant women, with diet as a key modifiable exposure pathway. These findings support the need for targeted dietary interventions and underscore the importance of updating health risk assessments to account for mixed bisphenol exposures.