By Erik Stokstad
Babies in rural counties of the United States that use a common weed killer are born slightly earlier and underweight, a large study finds. These changes, although small on average, could result in learning disabilities and an increased risk of infection, researchers reported last week in the Proceedings of the National Academy of Sciences, resulting in more than $1 billion in health care costs nationwide each year.
It’s a “very compelling and rigorous” study, says Eyal Frank, an environmental economist at the University of Chicago who was not involved. For the most vulnerable infants, in historically disadvantaged groups, the effect was significantly greater. “That’s the most alarming finding,” he says. Still, Frank and others note the research can’t prove the chemical known as glyphosate is to blame. For one thing, the study did not directly measure individual exposure to the active ingredient in the weed killer.
More than 127,000 tons of glyphosate are sprayed on U.S. fields each year, and the U.S. Environmental Protection Agency (EPA) and other regulatory agencies say it is safe to use with proper precautions. But some research suggests glyphosate can disrupt reproductive hormones in laboratory animals. In people, a small study in 2018 linked glyphosate exposure to slightly shorter pregnancy.