Association of specific PM2.5 chemical constituents and ozone exposure with pregnancy outcomes in women undergoing assisted reproductive technology treatment in central China

Abstract

The associations of air pollutants exposure with assisted reproductive technology (ART) pregnancy outcomes are mixed, and the effects of specific components of fine particulate matter (PM_2.5) and ozone (O₃) are not well understood. We conducted a retrospective longitudinal study to explore the association of PM_2.5 constituents and O₃ exposure with three ART outcomes among women undergoing ART treatment. The exposure window was segmented into five periods corresponding to the cycle of ovarian stimulation and oocyte retrieval procedure. Generalized linear mixed model (GLMM) was applied to explore the relationships between PM_2.5 constituents, O_3, Normalized Vegetation Index (NDVI) exposure and three ART outcomes. The combined effect of PM_2.5 constituents was evaluated by the quantile g (qg)-computation. We also explored the modifying effect of different covariate. Elevated exposure level of PM_2.5 (OR = 0.915, 95% CI: 0.859, 0.974) and its constituents (BC: 0.905, 95% CI: 0.840, 0.975; OM: 0.910, 95% CI: 0.848, 0.976; NO₃⁻: 0.909, 95% CI: 0.850, 0.972, SO₄²⁻: 0.905, 95% CI: 0.846, 0.968, and NH₄⁺: 0.902, 95% CI: 0.842, 0.966) exposure throughout the year before oocyte retrieval (period 1) was correlated with a reduced odds ratio (OR) of live birth with statistical significance. Similarly, for each interquartile range (IQR) increase in O₃ exposure during periods 2 (85 days prior to oocyte retrieval), 3 (30 days prior to oocyte retrieval), 4 (oocyte retrieval to embryo transfer) and 5 (embryo transfer to hCG test) was significantly related to a decreased OR of live birth. Especially, participants who underwent fresh embryo transfer cycles and received two cleavage-stage embryo transfer, and were younger than 30 years old, showed a higher susceptibility to particulate matter. Findings from this study suggest that PM_2.5 constituents and O₃ exposure may have adverse effects on the ART outcomes, highlighting the importance of identifying critical exposure periods for various air pollutants and the need for meticulous management of particulate matter.