Study Finds Wildfire Smoke and Heat Stress During Pregnancy Increase Risk of Adverse Birth Outcomes

Recent research from the Keck School of Medicine of USC highlights the negative impact of wildfire smoke exposure and heat stress on pregnancy outcomes, especially in environmentally vulnerable neighborhoods. Led by postdoctoral researcher Roxana Khalili, Ph.D., the study demonstrates that women exposed to these climate-related hazards before and during early pregnancy are more likely to give birth to infants with complications such as small-for-gestational-age (SGA) and low birth weight. The investigation, published in Environmental Science & Technology, utilized detailed fire data and advanced modeling to estimate wildfire smoke levels based on daily residential histories of pregnant women in Los Angeles. It also assessed heat stress through meteorological and geospatial tools, revealing that higher exposure correlates with increased risks for adverse outcomes.

The findings show that exposure during the month prior to conception and the first trimester significantly raises the odds of SGA infants—those weighing below the 10th percentile for their gestational age—and low-birth-weight babies. Living in neighborhoods more susceptible to climate risks further amplifies these effects, with women in such areas facing nearly double the risk of SGA births from heat stress during preconception. The research highlights the importance of understanding community vulnerabilities and the cumulative impacts of environmental stressors on maternal and infant health.

Given the increasingly severe and prolonged wildfire seasons, these insights stress the need for targeted interventions and community resilience strategies beyond individual precautions. As Khalili and her team emphasize, addressing infrastructure, socioeconomic factors, and environmental hazards holistically is essential to reduce health disparities and protect vulnerable populations from the compounded risks associated with climate change. This research underscores the urgency of developing comprehensive policies to support women’s health amid escalating climate crises.

Source: https://medicalxpress.com/news/2025-06-links-wildfire-exposure-stress-adverse.html