• Posted July 27, 2026

Weed-Killing Chemical Linked To Premature Births In Humans, Study Says

The active chemical ingredient in professional-grade Roundup weed killer might increase the risk of premature births, a new study says.

Pregnant women with higher urine levels of the chemical glyphosate were 35% more likely to deliver their child earlier than 37 weeks of gestation, researchers recently reported in the journal Environmental Pollution.

“Our findings add to a growing body of evidence that exposure to glyphosate early in life may lead to health concerns that can echo throughout a lifetime,” lead researcher Teresa Herrera, a doctoral candidate in population health at NYU Grossman School of Medicine, said in a news release.

Babies born prematurely are more likely to suffer illness and death, researchers said in background notes. They also face higher risks of breathing problems, infections and developmental delays.

Roundup manufacturer Bayer issued a statement calling the study's results into question.

“The study reports statistical associations but does not provide evidence that glyphosate exposure caused preterm birth or other adverse pregnancy outcomes,” Bayer’s statement read. “While associations were reported for preterm birth, the publication does not provide information sufficient to evaluate whether the observed findings represent a causal adverse health effect."

It continued: “Glyphosate has been used safely for 50 years and is among the most extensively studied products of its kind. Experts at the U.S. Environmental Protection Agency have reviewed hundreds of studies on glyphosate safety as part of the product registration process and determined that glyphosate is safe for use and does not cause reproductive or developmental harm. No regulatory authority in the world has determined that glyphosate causes reproductive or developmental harm.”

Glyphosate products are sprayed on commercial food crops as well as residential gardens and lawns, researchers said in background notes. Residues of glyphosate have been detected in cereals, snack foods, and fresh fruits and vegetables.

Lab studies in animals and cells have suggested that glyphosate might promote premature births by triggering inflammation, researchers said.

To further study the potential link, researchers tracked data on nearly 1,500 women participating in a children’s health study. The women planned to deliver at NYU Langone-affiliated hospitals in New York City between 2016 and 2019.

The women provided urine samples at two times during pregnancy – once between 4 and 17 weeks and again between 18 and 25 weeks.

Higher glyphosate urine levels at 18 to 25 weeks was associated with a 35% increased risk of preterm birth, even after researchers took other risk factors into account. 

Women who are concerned might limit their exposure by choosing organic grains and produce, Herrera said.

“These results underscore the need for stronger regulations to protect the health of pregnant women and infants, two groups long known to be especially vulnerable to chemicals in the environment,” senior researcher Dr. Leonardo Trasande, a professor of pediatrics at NYU Grossman School of Medicine, said in a news release.

“Organic farming methods can produce competitive yields, so the trade-off between weed control and long-term health risks is not as straightforward as is often portrayed,” Trasande said.

Researchers next plan to explore exactly how glyphosate exposure might affect fetal development and birth.

The Make America Healthy Again movement is strongly against glyphosate, but President Donald Trump in February issued an executive order promoting the production of the chemical. U.S. Health and Human Services Secretary Robert F. Kennedy Jr. supported the order, even though he spent years crusading against glyphosate as a MAHA point man.

More information

Penn State has more on health concerns related to glyphosate.

SOURCES: NYU Grossman School of Medicine, news release, July 22, 2026; Environmental Pollution, July 14, 2026