Prenatal Exposure to Wildfire Linked to Autism Risk in Children

TUESDAY, Jan. 27, 2026 (HealthDay News) — The risk for autism in children is increased in association with prenatal exposure to wildfire smoke, according to a study published online Jan. 20 in Environmental Science & Technology.

David G. Luglio, from the Tulane University School of Public Health and Tropical Medicine in New Orleans, Louisiana, and colleagues examined the effects of wildfire particulate matter diameter ≤2.5 µm (PM_2.5) on autism in a Southern California-based pregnancy cohort. Exposure was estimated from 2006 to 2014 at maternal addresses across pregnancy using three metrics: mean wildfire PM_2.5 concentration, number of days of smoke exposure, and number of waves of smoke exposure. The analyses were restricted to days over PM_2.5 concentrations of 3 and 5 μg/m³. Sensitivity analyses included nonmovers during pregnancy (75 percent of the cohort).

The researchers identified 3,356 autism diagnoses by age 5 years. There was an association for a greater number of wildfire-exposed days during the third trimester with autism risk, which was strongest for nonmovers. Hazard ratios (HR) for nonmovers were 1.108, 1.118, and 1.225 with exposure to one to five, six to 10, and >10 wildfire days, respectively, in the third trimester versus none. Per wildfire wave increase (>3 μg/m³ for two consecutive days) during the third trimester, the HRs were 1.073 and 1.267 for the entire cohort and nonmovers, respectively. No association was seen with the mean wildfire PM_2.5 concentration alone.

“Further study is needed to understand how wildfire smoke exposure to pregnant mothers could cause autism in their children, and to determine how exposure may interact with biology, genetics, and other environmental exposures,” Luglio said in a statement.

Abstract/Full Text