Pesticide Exposure Linked to Autism Spectrum Disorder in Residents of California’s Central Valley: von Ehrenstein et al., 2019

Prenatal and infant exposure to ambient pesticides and autism spectrum disorder in children: population based case-control study

O.S. von Ehrenstein, C. Ling, X. Cui, M. Cockburn, A.S. Park, F. Yu, J. Wu, & B. Ritz; BMJ, 2019, Volume 364.

Why It's Important:

Rising herbicide use means rising exposure for humans living in agricultural areas like California’s Central Valley.  Developmental impacts including autism symptoms have been associated with prenatal and early childhood exposure to herbicides like glyphosate in laboratory studies.  This epidemiological study adds to the body of evidence a compelling link between glyphosate exposure and autism spectrum disorder (ASD) in human populations.

What They Found:

California’s Central Valley is one of the most productive agricultural regions in the world.  As expected, herbicide use is widespread in the region (see map to the left – darker reds= more herbicides).

Researchers created a database of  people diagnosed with autism from 1998-2010 in eight target counties in the Central Valley.  They then used the state’s comprehensive pesticide reporting system CA-PUR to look at pesticide use – including herbicides – near these 3,000 residents diagnosed with autism over this time period.

A total of eleven pesticides were studied, including the insecticides chlorpyrifos and imidacloprid and the #1 herbicide in the world, glyphosate.

Development of autism was positively associated with exposure to some pesticides, especially during pregnancy.  Prenatal exposure to almost all the pesticides studied increased the relative risk of developing autism, but chlorpyrifos, avermectin, and diazinon were the most strongly associated with ASD.  Glyphosate showed a slight increase in risk of developing ASD when the exposure occurred in the first year of life.

But, a closer look at the results showed that exposure to some pesticides, including glyphosate and chlorpyrifos, was linked to a higher risk of a more severe cases of autism.


See this piece on our partner website Hygeia Analytics for a more detailed analysis.

See the full paper here, or click the following keywords to pull up more: herbicide use, developmental effects, glyphosate

About Us:

The Heartland Study is focused on birth outcomes in a 13-state region that 72 million Americans call home. Many doctors — and families — worry that it seems to be getting harder for women to get pregnant and carry a healthy child to term.

The Heartland Study is conducting cutting-edge scientific research that explores whether rising herbicide use is part of what is driving more frequent, and/or more serious reproductive problems and birth defects in the Midwest and beyond.