Franciscan Health doctor leads key study of pesticides in pregnant women

Nearly every sample studied revealed the presence of the commonly used pesticide.

Researchers were examining glyphosate, a weed killer, to determine if exposure affects the health and development of fetuses and newborns. Of 187 pregnant women studied in Indiana, 99% had the chemical in their system.

Furthermore, they found that exposure to glyphosate is associated with lower birth weights and may increase the risk for neonatal intensive care unit admissions.

“The first thing we noticed was the pregnancies were shorter with higher levels of glyphosate,” said Dr. Paul Winchester, neonatologist with Franciscan Health Indianapolis and principal author of the study. “Shorter pregnancy doesn’t sound like much, but it translates into more premature births. And premature birth is a big problem; it increases the risk of being in the (neonatal intensive care unit) and all kinds of lifetime changes.”

The world is paying attention to the work of Winchester and his fellow researchers. Their results were published in the scientific journal Environmental Health, showing for the first time the impact glyphosate has on human fetal development.

Though continued work is required to show how the weed killer affects other health outcomes, this initial study should give everyone pause about how glyphosate and other pesticides interact with our bodies.

“We should be alarmed that nearly every one of us, including our unborn children now get a dose of pesticides with every meal,” Winchester said. “We need to keep studying these herbicides long-term to find out how they could be contributing to these issues and what we can do to prevent them.”

Glyphosate is the most widely used broad-spectrum herbicide in agricultural, commercial and residential areas in the United States. The chemical has been in use for nearly 50 years, and has been heavily studied over that time.

In February 2020, the Environmental Protection Agency found that there are no risks of concern to human health when glyphosate is used in accordance with its current label. The agency also found that glyphosate is unlikely to be a human carcinogen.

Glyphosate is sprayed on acres of cotton, wheat, oats and barley as well as forests, lawns, gardens and roadways. As such, the pesticide and its metabolite residue is now found in nearly every food and many beverages, including wines.

“It’s found in virtually every food we eat, and is highest in some of the foods we think are the healthiest for us,” Winchester said. “It’s even found in organic honey.”

Previous studies conducted in animal models have shown a variety of ill-effects of pesticide exposure; however, little is known about the impact on human fetal development.

Winchester has been studying the effects of glyphosate for years. He came to Indiana 21 years ago, and one of his first impressions was that he was seeing more birth defects than he was used to seeing.

“I’ve been the director in multiple nurseries, starting in Colorado, Kansas, and New Hampshire, so I had a broad background in how babies are born in various states under certain hospital conditions,” he said.

When Winchester asked fellow pediatricians if they were seeing more defects, they responded that they were not. He also called the Centers of Disease Control to access records, at which time he was informed that Indiana did not track birth defects.

“I thought, how is that possible? It’s the leading cause of infant death in the U.S.,” he said.

In 2017, he led a study that found an association between heavier pesticide exposure and shortened pregnancy. This study served as the basis for more recent research to confirm that pre-term birth risk was higher in women with higher prenatal exposure to glyphosate.

The study was a collaboration with Franciscan Health, University of California-San Francisco, University of Arkansas for Medical Sciences, King’s College London School of Medicine and the Indiana University School of Medicine.

Winchester and his research colleagues studied a cohort of 187 pregnant women in Indiana by collecting urine samples during their first trimesters of pregnancy. All but one had glyphosate detected in their urine.

“To me, that’s an extraordinary finding,” Winchester said. “Using the most heavily used herbicide from the last 50 years, we neglected to measure pregnant humans to see if it was getting into their bodies.”

Lower weights — adjusted for pregnancy length — found in this study replicate what was found in a previous animal study performed by Winchester’s collaborator, Dr. Michael Skinner, professor of biological sciences at Washington State University.

In the animal study, lower birth weights led to higher rates of obesity in subsequent generations. The rise in the rates of obesity in humans has been recently reported by Winchester and others.

“In the rat model, if you’re born a little bit smaller because you’re exposed to glyphosate in utero, then your second- and third-generation descendants are obese at a rate of 60%,” Winchester said. “It’s an obese-generating chemical exposed in utero that dooms the child to an increased risk, not just him but his children as well. That’s what we showed in rats.”

Winchester and his colleagues’ work will continue in this field, as much more research is needed to determine the impact of pesticides in humans. But their study, so far, is cause for great concern.

“We are in the midst of a chemical era in which every creature on earth has these substances in our bodies,” Winchester said.