“Virtually all the major chronic diseases suffered from in adulthood can be linked to being smaller at birth.”
Glyphosate exposure during pregnancy is linked to lower birth weights for babies, according to a new study of pregnant people in Indiana.
Lower birth weights are associated with multiple health problems later in life, from diabetes to heart problems.
In the study, published earlier this month in Environmental Health, the research team also found that mothers with high-risk pregnancies who had higher glyphosate levels in their urine during the first trimester were also more likely to have babies admitted to neonatal intensive care units, or NICUs.
Related: Glyphosate, explained
Although the study looked at a limited number of pregnant people, it adds to a small but growing body of evidence linking the most commonly used weed killer in the world to potential pregnancy harms, John Meeker, a professor of environmental health sciences at the University of Michigan’s School of Public Health who was not involved with the study, told EHN.
Given the animal literature showing congenital disabilities and reproductive harms from glyphosate, the new study, Meeker added, “really further shines light on the need for more studies in this area.”
Rise in glyphosate brings health concerns
Glyphosate was originally marketed as a safer alternative to other herbicides, but as its use has grown, so too have concerns about its potential health effects. Of particular focus has been its potential to cause cancer, as highlighted by several recent high-profile lawsuits in the U.S., such as a class-action lawsuit in which up to 140,000 plaintiffs allege they developed a type of cancer called Non-Hodgkin’s Lymphoma due to Roundup use (glyphosate is the active ingredient in Roundup).
But researchers like Dr. Paul Winchester, study author and professor of clinical pediatrics at the University of Indiana Medical School, are also worried about pesticide exposure in the womb.
In an earlier study looking at glyphosate levels in pregnant people, Winchester and colleagues found glyphosate present in 94% of the expecting moms. “That was a huge surprise, that you went from a chemical that didn’t exist [on the market] to one that’s found in almost every pregnant mother,” Winchester, who is also a neonatal intensive care unit doctor, told EHN.
Given glyphosate’s potential impacts on pregnancy outcomes, he and other researchers looked specifically at people in Indiana with high-risk pregnancies in the new study. When the team sampled the group’s urine during the first trimester, they found glyphosate in 186 out of 187 — or 99% — of the people involved in the study.
The team also found a correlation between the amount of glyphosate in the urine and lower birth weight. Low birth weight contributes to breathing problems in newborns, difficulty feeding and even Sudden Infant Death Syndrome. A number of studies have also shown that it can have long-term effects on health and development. “Virtually all the major chronic diseases suffered from in adulthood can be linked to being smaller at birth,” Winchester said.
Stephanie Eick, a perinatal and environmental epidemiologist at the Rollins School of Public Health who wasn’t involved in the study, told EHN that exposure to glyphosate during pregnancy appears to be widespread. However, she noted, because the people in the new study were at higher risk for pregnancy complications, the reduction in birth weights might be associated with other factors and not glyphosate exposure.
“I think it's still too soon to know whether these are really causal associations, just because there have not really been a lot of studies that have looked at the effects of glyphosate during pregnancy,” she said.
Meeker, the University of Michigan professor, said that although the study was small, its findings were statistically significant. In a study in Puerto Rico, he and colleagues found a link between glyphosate exposure during pregnancy and premature birth.
Future studies should focus on pregnant people with higher exposure rates, like farm workers, and also sample throughout pregnancy due to how quickly glyphosate leaves the body, Meeker added. He would also like to see glyphosate measured in the National Institute of Health’s ECHO study, which looks at how environmental pollutants, demographics, genetics and other factors affect prenatal and other health outcomes in a national sample of people.
“That would be a perfect opportunity to get a broader national view of the impacts of glyphosate on pregnancy and child development,” he said.
Reducing glyphosate exposure
Monsanto, an agribusiness company now owned by Bayer, first sold glyphosate as a weedkiller in 1974. Use skyrocketed in the 1990s with the introduction of genetically modified crops that didn’t die when farmers sprayed Roundup and other glyphosate-containing herbicides. At least 250 million pounds of glyphosate are applied yearly on farms and the weedkiller is also commonly used in parks, playgrounds and home gardens.
People can be exposed to glyphosate by using weed killers, drinking water (especially if they’re in a farming community) and through residue on foods. Researchers suggest washing fruits and vegetables before eating them and eating organic, which has been shown to reduce glyphosate levels in our bodies quickly.
More broadly, this and other studies point to the need for the U.S. to do more aggressive safety testing on chemicals, as is done in Europe, Eick added.
“It doesn't seem to me that chemicals are really regulated at all before they're able to enter the U.S. market,” said Eick. “And so then the onus is really on the research scientist to figure out if the chemical is bad after we're already widely exposed.”