Background Per- and polyfuoroalkyl substances (PFAS) are categorized as persistent organic pollutants and commonly detected in humans, and their toxicity has attracted widespread attention. However, few studies have reported comparison of PFAS levels and potential factors between women pregnant using assisted reproduction technology (ART) and women pregnant naturally.

Objective To analyze and compare serum concentrations and sociodemographic determinants of PFAS in pregnant women conceiving through ART and conceiving naturally from Shanghai.

Methods Based on the China National Birth Cohort (CNBC) in Shanghai from 2017 to 2019, 333 pregnant women conceiving through ART and 689 pregnant women conceiving naturally were recruited during the same period as study subjects. The concentrations of 32 PFAS were measured in early-pregnancy serum of all pregnant women, and four PFAS with the highest co-exposure levels in both groups were included in the subsequent analysis. Multiple linear regression models were performed to evaluate the associations of sociodemographic factors with serum PFAS concentrations in the two groups respectively. Beta coefficients and 95% confidence intervals (CI) were exponentiated to calculate the ratio of the geometric mean (GM) of PFAS concentrations after each unit change in the independent variable.

Results Perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS), 6∶2 chlorinated polyfluoroethersulfonic acid (6∶2 Cl-PFESA), and perfluorohexanesulfonic acid (PFHxS) were four major PFAS in serum of pregnant women conceiving through ART and conceiving naturally, and the concentrations of PFOA, PFOS, and 6∶2 Cl-PFESA were higher in pregnant women conceiving through ART than in pregnant women conceiving naturally (P <0.05). The results of multiple linear regression analysis showed that age at pregnancy and household income were associated with serum PFAS levels in both groups. The serum concentrations of PFOS were higher in pregnant women aged ≥35 years old who conceiving through ART (GM ratio=1.26, 95%CI: 1.04, 1.54) and conceiving naturally (GM ratio=1.24, 95%CI: 1.08, 1.42) than pregnant women aged <30 years old respectively. Pregnant women conceiving through ART and conceiving naturally whose household annual income >300000 CNY had lower serum concentrations of PFOA GM ratio (95%CI): 0.82 (0.72, 0.95) and 0.89 (0.81, 0.97), respectively and PFHxS GM ratio (95%CI): 0.66 (0.51, 0.86) and 0.77 (0.66, 0.90), respectively than those women whose household annual income <200000 CNY. Additionally, pregnant women conceiving naturally with a graduate education or above had lower serum 6∶2 Cl-PFESA concentrations than women with an education below college (GM ratio: 0.81), and multiparous pregnant women conceiving naturally had higher serum concentrations of PFOS, 6∶2 Cl-PFESA, and PFHxS than primiparous pregnant women (GM ratio: 1.14, 1.25, and 1.27 respectively).

Conclusion Although differences in serum PFAS levels are found between pregnant women conceiving through ART and women conceiving naturally in this study, maternal age and household income are common determinants of PFAS exposure levels in both populations. We find no special sociodemographic factors to affect PFAS concentrations of pregnant women conceiving through ART compared to pregnant women conceiving naturally. Further research is required to explore other potential factors.