Did weed killer affect Indiana women's pregnancies?

A new study links the active ingredient in weed killers – glyphosate – to shortened pregnancies in Central Indiana women.

However, researchers are puzzled over how exactly the women in the study were exposed to it.

The environmentally pervasive chemical was detected in more than 90 percent of the 71 women tested, according to the study.

Where it wasn’t found was in the women’s drinking water, leaving researchers scratching their heads.

“It is a worldwide problem. Glyphosate is everywhere,” said Shahid Parvez, assistant professor in the Department of Environmental Health Science at the IU Richard M. Fairbanks School of Public Health at IUPUI.

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Parvez was the principal researcher of the study, which included women from nine Central Indiana counties.

The study by researchers from Indiana University and the University of California, San Francisco, is the first time exposure to the chemical in pregnant women has been directly measured using urine samples.

Their investigation found a direct correlation between the higher levels of the chemical in the women and the length of their pregnancies. Two of the infants in the study were born prematurely.

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Parvez said he is hopeful the investigation will encourage more extensive studies.

Glyphosate is one of the most heavily used agricultural weed killers in the world, according to the study. Nearly 300 million pounds of it are applied in the United States every year, especially to corn and soybean crops in the Midwest, leading to agricultural runoff of the chemical into streams, rivers and lakes.

Despite evidence of its environmental effects, Parvez said there hasn’t been much research into its effect on human reproduction. Past studies indirectly measured exposure to the chemical.

How were the women exposed to it?

Although there wasn’t much diversity to the age, racial backgrounds or geography of the women, they did come from a variety of rural, suburban and urban addresses with both public and private drinking water sources.

The highest levels were found in the women living in rural areas and those who consumed more drinks with caffeine, according to the study results.

Parvez theorizes that use of the herbicide where coffee beans are grown might account for the caffeine link.

More than 90 percent of the women used public drinking water. The chemical was not detected in any of the drinking water samples from the study, leading researchers to include it was being removed during water treatment.

Only about 20 percent of the women lived in rural areas. Although their levels were higher, none of them reported being involved in farming or directly applying the weed killer.

Drinking water was tested but home air quality was not, so researchers could not say if those women were exposed to it in the air.

Parvez said one possible explanation for the exposures of all the women in the study might be through what they ate.

In addition to being sprayed directly on crops, glyphosate residue also is present in seeds pretreated to make crops resistant to the weed killer when farmers apply it.

What does this mean for people?

Parvez said there isn’t enough information yet to definitively say the high glyphosate levels caused the women’s shorter pregnancies or how they were exposed.

It does imply, however, that genetically modified foods and drinks with caffeine might be the source.

“I would say as a precautionary measure people might want to try to eat organic foods,” he said.