Pregnant women living within a mile of fields where pesticides were applied faced almost double the risk of having a baby who developed autism -- compared to women who lived more than a mile away, a new study finds.
U.C. Davis researchers tracked pesticide applications on farms in the Central Valley, near Sacramento, and the Bay Area and matched that data to the addresses of women who lived nearby when they were pregnant.
The fetus tends to be vulnerable to certain kinds of insults," said Irva Hertz-Picciotto, an environmental epidemiologist at the MIND Institute at U.C. Davis and lead author of the study. "Pesticides may be one of those sets of chemicals that we need to be particularly careful about.
The study was published Monday in Environmental Health Perspectives.
Studies linking autism with pesticide use are new and not wholly accepted within scientific circles. Clare Thorp is a scientist with Crop Life America, a trade association for pesticide producers. She says this kind of geographic-based research is limited. Just because women lived near fields where pesticides were used doesn't mean they were actually exposed to the compounds.
"People who are at these addresses, they're not always going to be standing out in their garden. They're going to be inside the house or they might be at work, or they could be in the grocery store," Thorp said.
She says the study never verified if pesticides entered women's bodies by testing their skin or blood.
HealthDay reports that the authors of the study agree that this research represents only a small piece of the autism puzzle:
"These neurodevelopment disabilities are not the function of a single factor," said Hertz-Picciotto. "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," she said.
But based on her study, she said pregnant women should be aware that some of the chemicals found in commercial pesticides, like pyrethroids, are also sold for use around the home.
Even worse, they're sometimes labeled as "all natural" products, because they're based on a chemical that comes from chrysanthemum flowers. But Hertz-Picciotto says there's nothing natural about them.
"It's a synthetic product that's been designed to be more toxic than the natural product it's imitating," she said.
Hertz-Picciotto recommends that pregnant women with insect problems play it safe by looking for less toxic alternatives.