The latest research echoes earlier studies that found women exposed to the herbicide were more likely to have shorter pregnancies, which can increase babies' risk of long-term health problems.
Women exposed to the herbicide glyphosate were more likely to experience shorter pregnancies, according to a study published last week in the journal Environmental Research.
Glyphosate is the active ingredient in the widely-used herbicide Roundup. Most research on the health effects of glyphosate has focused on workplace exposures — people who work in agriculture and as groundskeepers, for example — and on cancer outcomes. The new study joins a small but growing body of research in the United States exploring the health risks of glyphosate exposure during pregnancy.
Glyphosate study follows several others
Researchers tested urine samples from a racially and geographically diverse cohort of 163 pregnant women in California, Washington, Minnesota, and New York. They detected glyphosate in more than 94 percent of the samples and found an association between glyphosate exposure and shorter pregnancies.
This latest study follows two others on glyphosate and pregnancy length, including a 2018 study of 71 pregnant women in Indiana which found that more than 90 percent had glyphosate in their urine. Those with higher glyphosate levels were more likely to have shorter pregnancies, which can increase the risk of infant mortality and long-term health challenges like breathing difficulties and intellectual delays.
First author Corina Lesseur, an assistant professor in the Department of Environmental Medicine and Public Health at Mount Sinai's Icahn School of Medicine, cautioned about the limitations of the new, relatively small study that focused on a single time point and did not identify the specific sources of the women's glyphosate exposure. Further research, she said, will be necessary to confirm the results in larger populations and to ascertain additional exposure effects on pregnancy and infant health.
"Glyphosate is unavoidable"
But the results underscore the importance of understanding glyphosate's health impacts beyond cancer, said corresponding author Jia Chen, also a professor at Mt. Sinai. She added that the study raises questions about potential effects of even low-dose exposures to glyphosate among the general population, since the glyphosate levels in the women's bodies were well below current U.S. regulatory thresholds.
"Glyphosate is unavoidable, it's even in rainwater," Chen said. "I would want to know if the regulatory levels are really safe. They may not cause DNA mutations, for example, but they may have other effects."
Glyphosate-based herbicides are the most commonly used in the world. Residue has been widely detected in food as well as in soil, dust, and drinking water. Multiple studies have found widespread exposure to glyphosate in the general population, with exposure rates increasing dramatically in recent years. Glyphosate has been linked to an array of health problems, including birth defects, DNA damage, endocrine disruption, reproductive problems, and cancer.
Tens of thousands of people have filed U.S. lawsuits alleging health problems caused by Monsanto's glyphosate-based weedkiller Roundup. The agrochemical company was acquired by Bayer AG in 2018. Last week, Bayer announced it would remove glyphosate from all lawn and garden products sold in the United States by 2023 to manage future litigation risk.
Bayer said no changes were planned for its professional and agricultural market products, however, which constitute the largest uses.