Prenatal exposure to heavy metals may raise likelihood of a child having ASD

Prenatal exposure to heavy metals may increase the likelihood of a child having an autism spectrum disorder (ASD), according to U.S. researchers.

Pi-I Debby Lin and colleagues analyzed 479 blood samples and 482 urine samples from pregnant women to determine if prenatal exposure to heavy metals affected their children’s scores on the Social Responsiveness Scale-Second Edition (SRS-2)—a measure of traits associated with ASD—or the odds of the children having ASD. They report, “Analyses of individual metals revealed that maternal blood lead and mercury levels were associated with increased autism-related traits, whereas urinary metals showed no meaningful associations. Additionally, we observed a significant association between maternal blood cadmium levels and an ASD diagnosis in children.”

Testing combinations of metals, the researchers found that higher maternal blood levels of arsenic, cadmium, mercury, and lead were associated with elevated SRS-2 scores on social awareness and cognition. Some differences in vulnerability to heavy metals were seen between males and females, which the researchers say “suggest[s] potential sex differences in susceptibility to metal-related neurodevelopmental effects.”

They conclude, “These results highlight the importance of reducing harmful metal exposures during pregnancy and considering combined exposures and sex-specific effects when evaluating risks to early brain development.”

Ciations

“Associations of prenatal metal exposures with autism-related outcomes in the ECHO cohort,” Pi-I Debby Lin, Andres Cardenas, Kristen Lyall, Deborah Bilder, Debra A. Mackenzie, Sara Nozadi, Brandon J. Rennie, Rebecca Schmidt, Heather Volk, Aisha S. Dickerson, amd Emily Okena, Environmental Epidemiology, July 2026 (free online). Address: Pi-I Debby Lin, Division of Chronic Disease Research Across the Lifecourse, Department of Population Medicine, Harvard Medical School and Harvard Pilgrim Health Care Institute, 401 Park Dr., Suite 401, East Boston, MA 02215, [email protected]