Connection seen between green space exposure in pregnancy, odds of ASD

Increasing the exposure of pregnant women to greenspace—grass, trees, or other vegetation—may reduce the odds of their children having an autism spectrum disorder (ASD), according to U.S. researchers.

Bethsaida Cardona and colleagues compared 245 children diagnosed with ASD to 1,526 controls matched by birth year. They determined greenspace exposure using satellite data that measured the density of vegetation in the immediate vicinity of each woman or within a 10- to 15-minute walk.

The researchers detected an inverse relationship between immediate-vicinity greenspace exposure during the first trimester of pregnancy and ASD. “Specifically,” they say, “greenspace exposure during the first trimester was associated with a 25% decrease in the odds of ASD in a model adjusting for other time periods of exposure. No other three month exposure period (i.e., three months preconception, second trimester, third trimester, or three months post-birth) was associated with ASD diagnosis.” Adjusting for levels of PM2.5 —small airborne particles of pollution implicated as a factor in neurodevelopmental issues—did not alter the results.

Cardona and colleagues suggest several possible reasons for the association between maternal greenspace exposure and ASD. For example, they say, exposure to greenspace may help to reduce maternal stress during pregnancy, which some research associates with ASD. Greenspace exposure may also encourage physical activity, reducing the risk of maternal obesity and diabetes, and may reduce exposure to air pollution.

The researchers conclude, “Future research is warranted to confirm these findings in other populations and explore the pathways by which greenspace may mitigate risk. Implications for urban and city design provide compelling reasons to increase research in this field.”

Citations

“Association between greenspace exposure before, during, and after pregnancy and autism spectrum disorder in offspring,” Bethsaida Cardona, Hayon Michelle Choi, Kristen Lyall, Jaime E. Hart, Peter James, and Marc G. Weisskopf, Journal of Exposure Science & Environmental Epidemiology, February 27, 2026 (free online). Address: Kristen Lyall, AJ Drexel Autism Institute, Drexel University, Philadelphia 19104, PA, [email protected].