Associations between ambient air pollution and outcomes of in vitro fertilization in a heavily polluted city in China

Abstract Research question Does air pollution relate to the outcome of IVF in a heavily polluted city in China? Design A retrospective cohort study of 8,628 fresh, autologous IVF cycles was conducted for the first time at the Reproductive Medicine Center of Third Affiliated Hospital of Zhengzhou University between May 2014 and December 2018 (oocyte retrieval date). The exposure was divided into four periods (gonadotropin [Gn] injection to oocyte retrieval [OR] [P1], OR to embryo transfer [ET] [P2], one day after ET to ET +14 days [P3], and Gn injection to ET +14 days [P4]) and four levels (Q1–Q4 according to their 25th, 50th, and 75th percentiles). Results An interquartile range (IQR) increase (Q2 vs Q1) in particulate matter (PM) 10 during P3 and P4 and Sulfur dioxide (SO2) during P3 significantly decreased the clinical pregnancy rate (adjusted odds ratio [aOR]=0.81, 95%CI: 0.71–0.92 for PM10 of P3; aOR=0.87, 95%CI: 0.76–1.00 for PM10 of P4; aOR=0.82, 95%CI: 0.73–0.93 for SO2 of P3). In addition, PM10 was associated with an increased biochemical pregnancy rate (Q3 vs Q1: aOR=1.55, 95%CI: 1.09–2.19 for PM10 of P1) and decreased live birth rate (Q2 vs Q1: aOR=0.88, 95%CI: 0.77–0.99 for PM10 of P3). The multivariate regression results were consistent with that of multiple treatments propensity score method (PSM) for SO2 pollutants in P3 and PM10 pollutants in P4. Conclusion From the early follicular stage to the pregnancy test period, high concentrations of PM10 and SO2 may have a negative impact on IVF treatment outcomes in the study area.