Wildfire Smoke and Pregnancy: Risks and Mitigation Strategies

A University of Washington analysis found maternal exposure to wildfire smoke during pregnancy is associated with an increased risk of preterm birth.

The report describes a retrospective cohort of 20,034 births across the contiguous United States in which investigators examined associations between wildfire-specific PM2.5 exposure and preterm birth (<37 weeks). Exposure assessment combined satellite- and monitoring-derived wildfire PM2.5 metrics and counts of smoke days.

Mid-to-late pregnancy—particularly the second trimester—showed the strongest association with preterm delivery. Regional variation in smoke concentration and composition modified estimate precision and magnitude, with the Western U.S. showing the most consistent signals.

Practical mitigation options during smoke events include temporary relocation for episodes of sustained, high-intensity smoke and optimizing indoor air quality by keeping windows closed and using HEPA or portable air filtration.