Pesticides, Pregnancy and Autism Risk

There is certainly reason to believe that autism is becoming more common in the United States. In March 2014, the Centers for Disease Control and Prevention (CDC) reported that 1 in 68 American children had an autism spectrum disorder. What made this finding especially noteworthy is that this figure stood at 1 in 88 children just two years earlier. The CDC survey did not provide a reason for this 30 percent increase.

With autism spectrum disorders becoming more commonplace, many studies have sought to find possible explanations for this trend. One group of researchers has recently found that pesticides might influence a child’s risk of developing autism.

 Living near Pesticides

The study was authored by researchers from the University of California Davis’ MIND Institute (Medical Investigation of Neurodevelopmental Disorders). Appearing in the journal Environmental Health Perspectives, this report concluded that pesticides used on farms, golf courses and other public areas could be a factor behind autism diagnoses. Specifically, pregnant women living near such locations were more likely to give birth to a child with an autism spectrum disorder (ASD).

The amount of increased risk depended on the type of pesticide in question. Women who lived near places treated with organophosphate pesticides were 60 percent likelier to have children with an ASD. By the same token, the risk of both ASDs and Developmental Delays (DDs) was up to twice as high among children whose mothers were exposed to pyrethroids during the final trimester of their pregnancies.

These findings were based on a review of 970 children between the ages of two and five. Of this total, 486 had been previously diagnosed as being autistic, whereas developmental delays affected 168 children. The remaining 316 subjects had neither ASDs nor DDs, and were developing normally.

 Explaining the Study’s Findings

In order to explain the findings of their study, the authors theorized that the chemical compounds found in pesticides might negatively affect neurons, or the cells found in the nervous system. Pesticides effectively cripple the nervous systems of insects, causing the targeted bugs suffer paralysis and death. The authors suggest that these products can also adversely impact neurons in human infants. At such a young age, the filters that shield the brain from harmful chemicals are still developing. The researchers believe that this lack of protection could allow pesticides to reach the body’s neurons, interfering with their efforts to establish connections with one another.

 Limitations and Recommendations

There were some notable limitations involved in this research. For one thing, none of the children’s mothers had their pesticide exposure levels tested while pregnant. Instead, all of the children analyzed by the authors had been born two to five years prior. Secondly, the authors examined four separate classes of pesticides. Because of this, they were unable to identify the specific chemicals that could increase ASD/DD risk. The study also did not feature any information regarding the mother’s diets, nor did it investigate how frequently they were exposed to pesticides at work or at home.

The authors themselves acknowledge that their work does not definitively link autism and DD disorders to pesticide exposure. They also agree with the notion that autism and similar conditions are caused by multiple factors. The researchers contend that the study “strengthens the evidence linking neurodevelopmental disorders with gestational pesticide exposures.” Given the conclusions of their research, the authors advised pregnant women to be aware of the ingredients of household products, which can contain chemicals also found in pesticides.