Air pollution and fecundability in a North American preconception cohort study: Fid-Bau Portal

Air pollution and fecundability in a North American preconception cohort study

Wesselink, Amelia K. / Hystad, Perry / Kirwa, Kipruto / Kaufman, Joel D. / Willis, Mary D. / Wang, Tanran R. / Szpiro, Adam A. / Levy, Jonathan I. / Savitz, David A. / Rothman, Kenneth J. / ... [mehr]

Abstract

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Highlights • Residential ambient concentrations of particulate matter, nitrogen dioxide, and ozone were not strongly associated with fecundability, the per cycle probability of conception. • We examined concentrations during multiple critical windows of exposure. • This is one of the largest studies to examine this association among couples trying to conceive spontaneously.

Abstract Background Animal and epidemiologic studies indicate that air pollution may adversely affect fertility. However, the level of evidence is limited and specific pollutants driving the association are inconsistent across studies. Methods We used data from a web-based preconception cohort study of pregnancy planners enrolled during 2013–2019 (Pregnancy Study Online; PRESTO). Eligible participants self-identified as female, were aged 21–45 years, resided in the United States (U.S.) or Canada, and were trying to conceive without fertility treatments. Participants completed a baseline questionnaire and bi-monthly follow-up questionnaires until conception or 12 months. We analyzed data from 8,747 participants (U.S.: 7,304; Canada: 1,443) who had been trying to conceive for < 12 cycles at enrollment. We estimated residential ambient concentrations of particulate matter < 2.5 µm (PM2.5), nitrogen dioxide (NO2), and ozone (O3) using validated spatiotemporal models specific to each country. We fit country-specific proportional probabilities regression models to estimate the association between annual average, menstrual cycle-specific, and preconception average pollutant concentrations with fecundability, the per-cycle probability of conception. We calculated fecundability ratios (FRs) and 95% confidence intervals (CIs) and adjusted for individual- and neighborhood-level confounders. Results In the U.S., the FRs for a 5-µg/m³ increase in annual average, cycle-specific, and preconception average PM2.5 concentrations were 0.94 (95% CI: 0.83, 1.08), 1.00 (95% CI: 0.93, 1.07), and 1.00 (95% CI: 0.93, 1.09), respectively. In Canada, the corresponding FRs were 0.92 (95% CI: 0.74, 1.16), 0.97 (95% CI: 0.87, 1.09), and 0.94 (95% CI: 0.80, 1.09), respectively. Likewise, NO2 and O3 concentrations were not strongly associated with fecundability in either country. Conclusions Neither annual average, menstrual cycle-specific, nor preconception average exposure to ambient PM2.5, NO2, and O3 were appreciably associated with reduced fecundability in this cohort of pregnancy planners.