Reproductive
Ambient air pollution mixtures and fecundability in a preconception time-to-pregnancy cohort Michelle R. Klawans* Michelle Klawans Kathryn S. Konrad Ian D. Buller Johanna R. Jahnke Alexander P. Keil D. Robert McConnaughey Anne Z. Steiner Anne Marie Z. Jukic
Background: While previous studies have found associations between air pollution and fertility, none have used exposure mixtures models. This study aimed to assess the effect of ambient air pollution mixtures on fecundability. Methods: Time to Conceive participants were females aged 30-44 living in central North Carolina attempting to conceive and had no known history of infertility. Ambient concentrations of particulate matter less than 10 microns in diameter (PM10) or 2.5 microns (PM2.5), ozone (O3), carbon monoxide (CO), nitric oxide (NO), nitrogen dioxide (NO2), and sulfur dioxide (SO2) obtained from the U.S. Environmental Protection Agency were linked to geocoded residential addresses at enrollment. Five exposure windows were assessed: spermatogenesis, early follicle development, follicular and luteal phases of the menstrual cycle, and implantation. For each window and pollutant, we calculated average and single-day peak concentrations. Time to conception was the number of menstrual cycles from enrollment until a positive urinary home pregnancy test. We used quantile g-computation to estimate the association of a simultaneous quantile increase of all pollutant concentrations in an exposure window with the probability of conception, adjusting for attempt cycle number, season, age, BMI, education, parity, race/ethnicity, occupation, smoking, and alcohol use, and partner age, race/ethnicity, and smoking. Results: Participants (N=924) contributed 3,671 cycles, of which 626 were conception cycles. During early follicle development, a quantile increase in all pollutant concentrations at once was associated with a fecundability odds ratio of 1.185 (95% confidence interval: 1.004-1.398). No associations were observed for other exposure windows or peak pollutant concentrations in any exposure window. Conclusions: In areas of relatively low pollutant levels, exposure to ambient air pollutant mixtures does not appear to negatively impact the probability of conceiving.