A recent California-based study has uncovered a strong link between pesticides and autism. Researchers at the University of California, Davis, MIND Institute examined associations between specific classes of pesticides, including organophosphates, pyrethroids and carbamates, applied during participants pregnancies. The data revealed pregnant women who live in close proximity to fields and farms where chemical pesticides are applied experience a 66 percent increased risk of having a child with autism spectrum disorder or developmental delay.
“We mapped where our study participants lived during pregnancy and around the time of birth. In California, pesticide applicators must report what they’re applying, where they’re applying it, dates when the applications were made and how much was applied,” Hertz-Picciotto said. “What we saw were several classes of pesticides more commonly applied near residences of mothers whose children developed autism or had delayed cognitive or other skills.”
The study indicates that women who are pregnant should take special care to avoid contact with agricultural chemicals whenever possible. Different classes of pesticides had different effects. Organophosphates, particularly chlorpyrifos applications during the second trimester, were associated with an elevated risk of autism. Pyrethroids were moderately associated with autism, and carbamates were associated with developmental delay.
Approximately 200 million pounds of pesticides are applied in California each year. Chlorpyrifos, the pesticide most strongly linked to autism is applied to crops across the United States.
Researcher Irva Hertz-Picciotto cautions that we should find ways to reduce pesticide exposure, especially for pregnant women and young children. “We need to open up a dialogue about how this can be done, at both a societal and individual level,” she says.