Ambient air pollution and rate of spontaneous abortion

2024  Journal Article

Ambient air pollution and rate of spontaneous abortion

Pub TLDR

This study investigated the association between ambient air pollution and spontaneous abortion (SAB) incidence in North American couples trying to conceive. The study analyzed data from 4643 participants in the United States (U.S.) and 851 participants in Canada.

The results showed that higher concentrations of particulate matter 2.5 mm (PM2.5) were associated with a higher incidence of SAB in Canada, but not in the U.S. No significant associations were found between nitrogen dioxide (NO2) or ozone (O3) concentrations and SAB incidence.

The findings suggest that ambient PM2.5 exposure may increase the risk of SAB in Canada. However, further research is needed to understand the underlying mechanisms and to develop strategies for protecting pregnant individuals from air pollution.

 

College of Health researcher(s)

OSU Profile

Highlights

  • We found a positive association of ambient PM2.5 concentrations with spontaneous abortion in Canada, but not the USA.

  • NO2 and O3 concentrations were not appreciably associated with rate of SAB.

  • Results were relatively consistent across season and weeks of gestation.

  • Protection of pregnant individuals from air pollutionis an important measure to safeguard maternal and fetal health.

Abstract

Spontaneous abortion (SAB), defined as a pregnancy loss before 20 weeks of gestation, affects up to 30% of conceptions, yet few modifiable risk factors have been identified. We estimated the effect of ambient air pollution exposure on SAB incidence in Pregnancy Study Online (PRESTO), a preconception cohort study of North American couples who were trying to conceive. Participants completed questionnaires at baseline, every 8 weeks during preconception follow-up, and in early and late pregnancy. We analyzed data on 4643 United States (U.S.) participants and 851 Canadian participants who enrolled during 2013–2019 and conceived during 12 months of follow-up. We used country-specific national spatiotemporal models to estimate concentrations of particulate matter <2.5 μm (PM2.5), nitrogen dioxide (NO2), and ozone (O3) during the preconception and prenatal periods at each participant's residential address. On follow-up and pregnancy questionnaires, participants reported information on pregnancy status, including SAB incidence and timing. We fit Cox proportional hazards regression models with gestational weeks as the time scale to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for the association of time-varying prenatal concentrations of PM2.5, NO2, and O3 with rate of SAB, adjusting for individual- and neighborhood-level factors. Nineteen percent of pregnancies ended in SAB. Greater PM2.5 concentrations were associated with a higher incidence of SAB in Canada, but not in the U.S. (HRs for a 5 μg/m3 increase = 1.29, 95% CI: 0.99, 1.68 and 0.94, 95% CI: 0.83, 1.08, respectively). NO2 and O3 concentrations were not appreciably associated with SAB incidence. Results did not vary substantially by gestational weeks or season at risk. In summary, we found little evidence for an effect of residential ambient PM2.5, NO2, and O3 concentrations on SAB incidence in the U.S., but a moderate positive association of PM2.5 with SAB incidence in Canada.

Wesselink, A.K., Kirwa, K., Hystad, P., Kaufman, J.D., Szpiro, A.A., Willis, M.D., Savitz, D.A., Levy, J.I., Rothman, K.J., Mikkelsen, E.M., Laursen, A.S., Hatch, E.E., Wise, L.A.(2024)Ambient air pollution and rate of spontaneous abortionEnvironmental Research246