Picture of Medha Chandra

Medha Chandra

Pesticides, pregnancy & autism. Do we know enough?

Researchers found that mothers who live within a mile of fields where toxic pesticides are applied have a 60 percent higher chance of having kids with autism. The link is strongest for the insecticide chlorpyrifos — and as a mom, this has me worried.

On Monday, researchers from UC Davis released new data linking prenatal pesticide exposure to increased risk of autism. This latest study adds to an increasingly powerful case for reducing use of these harmful chemicals that are undermining the potential of the next generation.

Researchers found that mothers who live within a mile of fields where toxic pesticides are applied have a 60 percent higher chance of having kids with autism. The link is strongest for the insecticide chlorpyrifos — and as a mom, this has me worried. More than a million pounds of this chemical are used every year in California, and while both state officials and EPA are taking another look at chlorpyrifos harms, the process is painfully slow. That’s why we’re now asking Congress to step up and help protect our kids.

Rates of autism have skyrocketed in the past few decades. While some of this may be due to better reporting and diagnosis, health professionals agree that this cannot explain the sharp increase — and that there is likely a combination of genetics and environment at work.

The science linking chlorpyrifos and other organophosphate pesticides to neurodevelopmental damage in children just keeps getting stronger. This week’s study found that carbamate and pyrethroid pesticides can also increase risk of developmental delays and autism.

Ever stronger science

More and more studies are linking pesticides and other chemicals with increased autism risk. The UC Davis MIND Institute’s Childhood Autism Risks from Genes and Environment (CHARGE) study is an ongoing California research program which aims to uncover the broad array of factors contributing to autism and developmental delays.

Researchers advise pregnant women to avoid contact with pesticides “whenever possible”.

Since 2003, the CHARGE study has enrolled over 1,600 participants whose parents answer extensive questionnaires regarding environmental exposures including their place of residence during pregnancy.

In this particular study, data from 970 participants from California’s agriculture rich Central Valley were assessed. Organophosphate pesticides applied over the course of pregnancy were clearly associated with an elevated risk of autism spectrum disorder.

Timing of exposure was crucial. Chlorpyrifos exposures for pregnant women in the second trimester were clearly associated with higher risk of having children with developmental delays and autism. Pyrethroid exposures immediately prior to conception and in the third trimester were moderately associated with autism spectrum disorder. Carbamate exposures were associated with increased incidence of developmental delay.

The way forward

According to lead study author Janie F. Shelton, therse findings validate previous research linking autism and agricultural chemicals. She notes:

While we still must investigate whether certain sub-groups are more vulnerable to exposures to these compounds than others, the message is very clear: Women who are pregnant should take special care to avoid contact with agricultural chemicals whenever possible.

Seems to be sound advice — though it assumes that women are aware when pesticides are being used and can effectively avoid exposures. We know pesticides drift into rural communities in California’s Central Valley, and while we are one of the only states requiring detailed pesticide use reporting, neighbor notifications before application are rarely required.

For me, this study and others like it which keep strengthening the links between pesticides and children’s brain health lead to a fundamental question: how can we continue this model of agriculture where one hazardous pesticide is replaced by supposedly ‘safer’ pesticides, only to be found to be not so safe after all?

Case in point: use of pyrethroid pesticides, reputedly safer than the old organophosphates, has increased amidst claims that they are safer. As the UC Davis and other studies now show, relatively safer isn’t safe enough.

Weak regulations combine with high use of brain-harming pesticides to put our children at risk.

Add to this mix a flawed pesticide risk assessment and pesticide approval process, combined with high uses of brain-harming pesticides in California — even close to schools. In response to legal action by PAN and our partners, EPA now requires buffer zones around places where children live, learn and play to protect children from chlorpyrifos spray drift — but such protection remains far too little in light of the latest research.

Quite simply, it’s time to take brain-harming chemicals like chlorpyrifos off the market. Please join us in pressing Congress to make this a national priority, and put a stop to what public health officials are calling a “chemical brain drain”.

We need to invest in moving away from this pesticide treadmill and towards agroecology and safer ways of growing our food that are protective of people and the planet and yield bountiful crops.

On this journey towards safer, saner food production individuals can make a huge difference. Let’s work together to protect our children, our future. Here are some steps you can take to get started in reducing pesticide exposure in your community. Onwards!


Picture of Medha Chandra

Medha Chandra

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