January 21, 2026
Wildfire smoke linked to higher risk of preterm birth, UW study finds
About 1 in 10 babies in the United States are born prematurely, which poses serious health risks, making prevention critical for public health.
A new University of Washington study, analyzing more than 20,000 births, found that exposure to wildfire smoke during pregnancy increases the likelihood of preterm birth, especially during the second trimester when placental development is most active.
The risk was highest in the Western U.S., where smoke concentrations and exposure days were greatest, and researchers suggest that fine particles from smoke may reach the placenta and fetus. While more research is needed to understand the mechanisms, the researchers believe the evidence is strong enough to prompt tailored public health messaging and protective measures for pregnant people during smoke events.