A study of 970 children born in farm-rich areas in California was published in Environmental Health Perspectives. Researchers found that pregnant mothers living within one mile of crops treated with widely used organophosphate pesticides were 60% more likely to give birth to a child with autism. Most of the women lived in the Sacramento Valley.

The study is the first to report a link betweent the pesticide pyrethroids and autism. Application of pyrethroids just prior to conception increased the risk of having a child with autism by 82% and during the third trimester, the risk was 87%. This is concerning because the use of pyrethroids have increased over the past several years both in agricultural and home settings due to bans on other chemicals.

That finding is particularly concerning because “pyrethroids were supposed to be better, safer alternatives to organophosphates,” said the study’s senior author, Irva Hertz-Picciotto, an epidemiologist who leads the UC-Davis project to investigate environmental and genetic links to autism.

"These neurodevelopment disabilities are not the function of a single factor," said study author Irva Hertz-Picciotto, an environmental epidemiologist at the MIND Institute at University of California Davis. "I would suspect that there's a number of different factors at play that have to do with maternal health, maternal nutrition, as well as chemicals that are used around the home as well as other factors like air pollution. It's going to be an accumulation of factors for any one woman."

Even though researchers state that the risk of autism can increase due to a combination of factors, they say that pesticides alone could significantly contribute to an autism risk because pesticides affect neurons.

To read more, please visit Environmental Health Perspectives.