Pregnant women and pesticides: Exploring the possible autism connection

If highly exposed, you're more at risk for having kids with autism, study says

Could there be a connection between a mother’s exposure to pesticides during her pregnancy, and an increased risk for autism in her child?

One study says yes.

Scientists have been researching the potential effects of pesticide exposure on infants and developing fetuses, and they recently determined that exposure to the most commonly used pesticides was in fact linked to a higher risk of autism spectrum disorder.

These findings were published last month in “Prenatal and infant exposure to ambient pesticides and autism spectrum disorder in children: Population based case-control study,” in The BMJ, a peer-reviewed medical journal originally called the British Medical Journal.

This was a study that took place in the Central Valley, which is California’s main agricultural region, with scientists using 1998-2010 birth data from the Office of Vital Statistics. The study looked at about 38,000 people with 2,961 cases of autism.

Researchers examined autism registry data in the state, along with data on pesticide spraying in California.

Here are some findings: Pregnant women who lived in a 2,000-meter radius of a highly sprayed area were about 10% to 16% more likely to have children diagnosed with autism than women who lived in places farther from sprayed areas, the study found.

Time magazine also covered this story after the study was released and broke it down in an easily digestible way: “The researchers reviewed spraying of 11 popular pesticides, including chlorpyrifos, diazinon and permethrin (often used to control ticks). When they looked at diagnoses of autism spectrum disorder that also came with intellectual disabilities, they found on average 30% higher rates among children who were exposed to the pesticides while in utero. Exposure in the first year of life increased the risk of autism by up to 50% compared to those not exposed to certain pesticides.”

Previous research conducted in animals has linked some of these pesticides to potentially harmful effects on brain development, including on animals still in the womb, according to published reports. Perhaps that’s why Ondine S. von Ehrenstein, an associate professor at UCLA who led the study, chose to examine these pesticides in humans.

Also worth noting: This is a bit different than education on pregnant woman abstaining from drinking or smoking, for example, because those are obvious lifestyle choices. Some women might not even know if they’re exposed to pesticides, or about the areas in which they live.

The study, which is largely written for the medical community (read: not so easy to understand) seems to have taken many controls and factors into consideration. But it stands by its findings.

The research concludes with the words, “From a public health and preventive medicine perspective, our findings support the need to avoid prenatal and infant exposure to pesticides to protect early brain development.”

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