Associations between ambient air pollution and pregnancy rate in women who underwent in vitro fertilization in Shenyang, China.

To assess the associations between air pollution and the pregnancy rate of IVF, we performed a retrospective cohort study on 1455 women who underwent the first fresh IVF cycle at a fertility center from January 2014 to April 2018 and lived in Shenyang during treatment. Binary logistic regression models were used to evaluate the effect of an interquartile range increase in each pollutant on the intrauterine pregnancy rate. Both average chronic and daily acute exposure to air pollution were considered. Increased O3 (adjusted OR = 0.87, 95% CI: 0.81, 0.98) during the period from gonadotropins starting to oocyte retrieval was associated with decreased probability of intrauterine pregnancy, especially the day before oocyte retrieval (adjusted OR = 0.86, 95% CI: 0.78, 0.95). Our results suggest that exposure to O3 before oocyte retrieval has an adverse effect on intrauterine pregnancy. Future studies should be performed in order to confirm our findings.