A new in-depth study has been launched to measure the health effects of herbicides such as glyphosate, dicamba, and 2,4-D on mothers and infants living in the midwestern United States. The Heartland Study will try to answer the question: Is rising herbicide exposure leading to reproductive problems, adverse birth outcomes or developmental delays in America’s heartland?
Concerns about health impacts of herbicides in the Midwest
The idea for the study arose four years ago when Charles Benbrook, a researcher who has published studies on pesticide use, was approached by individuals at organic dairy producer Organic Valley who were concerned about increasing herbicide use in Wisconsin and its possible connection to reproductive problems in women and birth defects in infants. Benbrook proposed a multi-hospital clinical study with women and their babies in the Midwest to see if there was a connection.
“The focus of the study would be to determine whether the women who have higher levels of herbicide in their urine during pregnancy, which is a reliable marker of herbicide exposure, were more likely to experience observable and clear adverse birth outcomes,” Benbrook says.
Organic Valley provided initial funding, and Benbrook was then able to secure the rest of the funding to launch the project. Benbrook says one reason he was able to fund the project was because there are concerns about health impacts of herbicides in the Midwest.
“The effect of herbicide exposure on reproductive health and development is an issue that many people in the Midwest are concerned about, despite the fact that it doesn’t really get a lot of attention. It’s one of those issues that’s generally not appropriate for public conversation because it’s so sensitive and controversial,” he says.
Herbicide use expanding dramatically
As concerns about the health impacts of herbicides are growing, herbicide use in the Midwest is expanding dramatically. Glyphosate, the main ingredient in Roundup, is used widely on corn and soybeans that are genetically engineered to tolerate the weedkiller. In recent years, an increasing number of weeds have developed resistance to glyphosate, leading farmers to use even greater quantities of the herbicide. An estimated 300 million pounds of glyphosate are used each year in the U.S. with more than three-fifths of that used in the Midwest with its high concentration of farms.
To address the weed resistance problem—and to keep farmers on a pesticide treadmill—biotechnology companies have introduced genetically engineered soybeans and cotton that are used with another herbicide, dicamba. But the use of dicamba has been a disaster with its tendency to volatize and travel for miles, damaging other crops, trees, and gardens. This past June, a U.S. Court of Appeals overturned the approval of three dicamba formulas, ruling that the U.S. Environmental Protection Agency broke the law in approving the herbicide.
Meanwhile, a growing body of research is documenting negative health and environmental impacts of glyphosate, which has been classified as a probable human carcinogen by International Agency for Research on Cancer of the World Health Organization.
Leading scientists and partner institutions
According to Benbrook, the study has assembled a team of leading scientists and partner institutions. The study’s lead scientists are Melissa Perry, research professor and interim associate dean for research with the Department of Environmental and Occupational Health at George Washington University, and Dr. Paul Winchester, medical director of the Neonatal Infant Care Unit at Franciscan Health Indianapolis and professor of clinical pediatrics at Riley Children’s Hospital in Indianapolis, IN. Hospitals collaborating with the study include Gundersen Medical Center in La Crosse, WI and Franciscan Health in Indianapolis, IN. There is also a science advisory board comprised of physicians and scientists with expertise in pediatrics, public health, and epidemiology.
“We have a great interdisciplinary team of scientists from both the U.S. and some of our partners in Europe,” says Benbrook who is a member of the science advisory board.
Testing 2,000 mothers and infants
The study will involve testing the urine and measuring herbicide levels of 2,000 mother and infant pairs living in the Midwest. Urine testing will be done by the U.S. Centers for Disease Control and Prevention (CDC) and will involve testing for glyphosate, dicamba, and 2,4-D herbicides.
“We’re really pleased to be working with the CDC given that they have the highest quality analytical methods in the country that are the most trusted by scientists,” Benbrook says. “We have an incredible opportunity to tap into cutting edge science in genomics, toxicology, epidemiology, and neonatology.”
The study will also track pregnancy outcomes and monitor the health and development of the infants for at least the first three years of their lives.
A key aspect of The Heartland Study will be to track inheritable epigenetic changes resulting from herbicide exposure. These are changes that are passed on to several generations. Dr. Winchester is a pioneer in this area of research, having published studies showing how pesticide damage to DNA can be “programmed” into future generations.
Benbrook expects the first results from the study to start being reported by the end of 2021.
The Heartland Study isn’t the first to examine the link between herbicide exposure and birth outcomes. A 2018 study published in Environmental Health linked glyphosate levels in women with shorter pregnancies. Dr. Winchester was a co-author of that study.