Acute effects of air pollutants on spontaneous pregnancy loss: a case-crossover study

This case-crossover study found that short-term expo- sure to ambient NO2 increased the risk of spontaneous pregnancy loss by 16% in 1,398 women in Utah from 2007 to 2015.

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Volume 111, Issue 2, Pages 341–347


Claire L. Leiser, M.S.P.H., Heidi A. Hanson, Ph.D., M.S., Kara Sawyer, M.D., Jacob Steenblik, M.P.H., M.H.A., Ragheed Al-Dulaimi, M.D., M.P.H., M.Sc., Troy Madsen, M.D., Karen Gibbins, M.D., James M. Hotaling, M.D., Yetunde Oluseye Ibrahim, M.D., James A. VanDerslice, Ph.D., Matthew Fuller, M.D.



To investigate the relationship between acute exposure to air pollutants and spontaneous pregnancy loss.


Case-crossover study from 2007 to 2015.


An academic emergency department in the Wasatch Front area of Utah.


A total of 1,398 women who experienced spontaneous pregnancy loss events.



Main Outcome Measure(s)

Odds of spontaneous pregnancy loss.


We found that a 10-ppb increase in 7-day average levels of nitrogen dioxide was associated with a 16% increase in the odds of spontaneous pregnancy loss (odds ratio [OR] = 1.16; 95% confidence interval [CI] 1.01–1.33; P=.04). A 10-μg/m3 increase in 3-day and 7-day averages of fine particulate matter were associated with increased risk of spontaneous pregnancy loss, but the associations did not reach statistical significance (OR3-day average = 1.09; 95% CI 0.99–1.20; P=.05) (OR7-day average = 1.11; 95% CI 0.99–1.24; P=.06). We found no evidence of increased risk for any other metrics of nitrogen dioxide or fine particulate matter or any metric for ozone.


We found that short-term exposure to elevated levels of air pollutants was associated with higher risk for spontaneous pregnancy loss.

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Fertility and Sterility

Editorial Office, American Society for Reproductive Medicine

Fertility and Sterility® is an international journal for obstetricians, gynecologists, reproductive endocrinologists, urologists, basic scientists and others who treat and investigate problems of infertility and human reproductive disorders.