Wildfire smoke exposure during pregnancy linked to higher autism risk in children

Published on 29 October 2026 - 7:12 GMT+1 Children whose mothers were exposed to fine particulate matter from wildfires during pregnancy were more likely to receive an autism diagnosis, according to a new study. ADVERTISEMENT ADVERTISEMENT Each 0.75-microgram-per-cubic-metre increase in the average concentration of wildfire-related fine particles during pregnancy was associated with a 30% higher risk of developing autism. The strongest associations with autism happened during the second and third trimesters. “Pregnancy is a period of rapid brain development, when environmental exposures may interfere with important developmental processes,” said Stefania Papatheodorou, an epidemiologist at the Rutgers School of Public Health and lead author of the study. Autism is linked to complex neurodevelopmental processes that begin before birth, when the brain is rapidly developing and connections between nerve cells are forming. She added that the findings highlight the importance of monitoring wildfire events and their potential effects on air quality during pregnancy. The study included around 900,000 mother-child pairs in the United States, who were followed for an average of 6.3 years. Wildfire smoke contains fine particles, gases and other pollutants. Its composition can vary depending on what is burning, as fires may consume plastics, electronics and paints that release toxic chemicals into the air. These particles can penetrate deep into the lungs and contribute to inflammation throughout the body. This is one possible pathway through which exposure could affect pregnancy and fetal development. “Wildfire smoke can travel far beyond the communities where fires are burning, and exposure may occur even when smoke is not visible,” Papatheodorou said. It has been linked to several health impacts such as asthma, chronic pulmonary and mental health conditions. The study was observational and cannot establish a causal link between wildfire smoke exposure and autism, the researchers noted. “Understanding how prenatal environmental exposures may contribute to autism, alongside genetic and other factors, remains an important research priority,” Papatheodorou said. Measures to reduce smoke exposure during pregnancy, including improved air-quality forecasting and strategies to limit smoke entering indoor spaces, could help protect maternal and child health.