Environmental pollution and human fertility: investigating the relationship between PM2.5 exposure and assisted reproductive technology outcomes.

OBJECTIVE

To investigate the impact of seasonal variations in particulate matter with an aerodynamic diameter of 2.5 µm or less (PM2.5) exposure on assisted reproductive technology (ART) outcomes.

METHODS

This retrospective study, conducted at the First People's Hospital of Shangqiu, analyzed data from 13,476 patients who underwent ART procedures between February 2018 and December 2022. Patients were categorized based on seasonal PM2.5 exposure levels. A generalized additive model (GAM), linear regression analysis, and multivariate logistic regression were used to assess the relationship between PM2.5 exposure and ART outcomes, including oocyte and embryo quality, pregnancy rates, live birth rates, and miscarriage rates.

RESULTS

Significant differences were observed in oocyte number, metaphase II (MII) oocyte number, transferable embryos, and good-quality embryos across seasonal PM2.5 exposure subgroups. Pregnancy rates and live birth rates also demonstrated statistically significant variations. Linear regression analysis revealed a consistent negative correlation between PM2.5 concentrations and key ART outcomes. Multivariate logistic regression analysis, adjusting for age and seasonal variations, confirmed a significant negative association between PM2.5 exposure and both pregnancy rates (OR = 0.995, 95% CI: 0.994-0.996, p < 0.001) and live birth rates (OR = 0.996, 95% CI: 0.995-0.997, p < 0.001). However, no significant relationship was found between PM2.5 exposure and miscarriage rates. GAM analysis further identified a nonlinear, threshold-like association between pregnancy outcomes and predictive factors, with significantly higher live birth rates observed in spring, summer, and autumn compared to winter.

CONCLUSIONS

The study complements existing evidence that exposure to PM2.5 can lead to decreased success rates of pregnancy and live births, as well as significantly impact the outcomes of ART. Future research should focus on developing strategies to mitigate the adverse effects of environmental pollution on ART success rates.