O-214 interaction of air pollution and meteorological factors on IVF outcomes: a multicenter study in China

Abstract Study question Is there an interaction between air pollution and meteorological factors on IVF outcomes? Summary answer The correlation between air-pollutant exposure and IVF outcomes was modified by meteorological conditions, especially temperature and wind speed. What is known already Previous studies revealed associations between air-pollutant exposure and in vitro fertilization (IVF) outcomes. However, modification effects of air pollution on IVF outcomes by meteorological conditions remain elusive. Study design, size, duration Multicenter retrospective cohort study, 2015–2020. Participants/materials, setting, methods This multicenter retrospective cohort study included 15,217 women from five northern Chinese cities during 2015–2020. Daily average concentrations of air pollutants (PM2.5, PM10, O3, NO2, SO2, and CO) and meteorological factors (temperature, relative humidity, wind speed, and sunshine duration) during different exposure windows were calculated as individual approximate exposure. Generalized estimating equations and stratification models were used to assess the associations of air pollution and meteorological conditions with IVF outcomes and estimated potential interactions. Main results and the role of chance Exposure to PM2.5, SO2, and O3 was adversely correlated with pregnancy outcomes in fresh IVF cycles. Positive associations of wind speed and sunshine duration with pregnancy outcomes were detected. In addition, we observed that embryo transfer in spring and summer had a higher likelihood to achieve a live birth compared with winter. In stratified models, pieces of evidence of interaction between meteorological factors and air pollutants on pregnancy outcomes were detected. Negative associations of PM2.5 with clinical pregnancy were only significant at lower temperatures and wind speeds. Moreover, the effects of O3 on live birth were enhanced by higher quartiles of wind speed. Limitations, reasons for caution First of all, we used the data from monitoring stations to estimate the individual exposure, which was inaccurate and may introduce bias. Second, due to data limitations, this study did not discuss socio-economic factors, which were reported to be associated with spatial-temporal variations of air pollutants and reproductive outcomes. Wider implications of the findings Pregnant women should be advised to reduce outdoor time when the air quality was poor, particularly at lower temperatures. Trial registration number not applicable