May 15, 2026 | Ethan Simmons
New research is testing effective ways to communicate with families about chemical exposures
Among the last things a mother wants to hear is that chemical compounds found nearly everywhere in the modern environment—our clothing, packaging, plastics and drinking water—could have implications for their child’s development in the womb.
Sarah Geiger, assistant professor of health and kinesiology at the College of Applied Health Sciences at the University of Illinois Urbana-Champaign, has studied the adverse impacts of environmental pollution and chemical exposures on human development for more than 15 years as a researcher.
Now she’s part of emerging research to hone those conversations: how do we communicate these findings without creating undue levels of fear or concern?
“You don’t want them to feel like, ‘Great, now I’ve somehow unknowingly put my developing child at risk,’” Geiger said. “The conversations we try to have with mothers is, ‘Here’s what we know so far and here’s what we’re trying to learn; here’s what could be the case, or not.
“We also equip them with knowledge to empower them to avoid chemical exposure in a way that is tailored to their individual chemical measures, as well as protective behaviors that could help to mitigate any effects of existing chemical exposure.’”
This process, known as ethical report-back of research results (“report-back”) is a science unto itself. With an R01 grant from the National Institutes of Health, Geiger is collaborating with the Silent Spring Institute—a women’s and environmental health research organization—and colleagues at the University of California San Francisco to experiment with the report-back process.
Geiger has teamed up with Silent Spring and UCSF previously to make a tutorial for research participants to understand chemical exposure. In this new study, participants will be tracked on several biomarkers that have not typically been reported back to participants—like telomere length, oxidative stress and inflammation—then informed of the results in separate groups.
“We’re doing a randomized controlled trial, not with vaccines or pharmaceutical products, but with report-back,” Geiger said. “If one study group gets the report-back report, and the other received their results with a feature designed to facilitate them taking action around these results, are there differences in behavior change outcomes?
“The idea is that we want to learn what best helps research participants understand and act on their individual results in a way that has the potential to enhance health.”
The report-back process is important because our polluted environment isn’t going away. Even as larger studies, including a birth cohort study hosted at the University of Illinois, continue to reveal how common chemicals impact children’s development, the United States industrial ecosystem doesn’t seem to be improving, Geiger said.
“Most of the chemicals far and away that I’ve studied are endocrine-disrupting. And the situation is not getting better—it’s getting worse because we’re stripping away environmental regulations in this country,” Geiger said. “Whatever your political persuasion is, the reality is that we don’t abide by the precautionary principle for chemical exposures and chemicals in products to the extent that our counterparts in other developed nations do.”
Understanding ‘forever chemicals’
Among the many compounds Geiger studies as an environmental epidemiologist, so-called “forever chemicals” are recurring characters.
Per- and polyfluoroalkyl substances, or PFAS, are manmade compounds used in water-resistant clothing, stain-resistant food packaging, nonstick cookware materials and countless other consumer products. Also found in drinking water, PFAS earned the moniker of forever chemicals for their durability and tendency to accumulate in human and animal bodies.
PFAS were long considered chemically inert. But a crisis in middle America opened new investigations into their health effects, and Geiger had a front-row seat.
For decades, chemical producer DuPont knowingly dumped perfluorooctanoic acid, called PFOA or C8, in the Ohio River, which flowed into drinking water for the surrounding communities. DuPont used C8 to produce nonstick Teflon products.
In 1998, more than 70,000 residents of the mid-Ohio River Valley in West Virginia and Ohio reached a $671 million settlement with DuPont. The class action lawsuit also funded a massive cohort study to observe PFOA’s long-term effects on human health.
Geiger obtained her doctorate at West Virginia University School of Medicine, where many researchers were untangling the damage done.
“I was really interested in environment and human health—and pediatrics, too,” Geiger said. “I had a couple kids at that time: I was interested, partially just from being a mom, in child development.”
What they learned: PFAS disrupts human endocrine systems. PFAS chemical structures are similar to the sex hormones estrogen and testosterone. Significant adult exposure is associated with kidney and testicular cancer risk, lowered fertility, and damage to the immune system.
Other common endocrine disruptors include bisphenol A, a chemical used in plastic manufacturing which coats the insides of metallic products like food and beverage cans, and parabens, preservatives commonly found in cosmetic products like shampoos and moisturizers.
Exposure to endocrine disruptors in utero can disrupt and complicate children’s pre-birth sexual development and affect their developmental trajectory years down the line—leading to lower birth rate, decreased bone density and accelerated puberty.
“How can a chemical exposure for a developing fetus in the womb change child behavior at age 5? Physically, chemically, how in the world does that happen? That’s what we’re trying to get to the bottom of,” Geiger said.
Geiger is an investigator on the Illinois Kids Developmental Study, or IKIDS, a cohort study led by neuroscientist Susan Schantz at the Beckman Institute at Illinois.
Prospective human cohort studies are the gold standard in epidemiology. They enroll participants and follow up with them for years or even decades, collecting relevant health data to find patterns in their development and life outcomes.
In IKIDS, pregnant women are enrolled early in their pregnancy and continue to check in from their child’s birth up to age 8 in many cases. More than 600 mothers, fathers and their children have been enrolled so far, and they’ve secured funding from the National Institutes of Health to continue the study through 2030.
“I was really interested in environment and human health—and pediatrics, too. I had a couple kids at that time: I was interested, partially just from being a mom, in child development.”
Sarah Geiger
HK Assistant ProfessorSome participating mothers have been tested on a variety of chemical exposures in their blood during pregnancy. Their kids’ development is tracked for any significant associated outcomes, particularly around neurodevelopment, or the growth of the brain and nervous system.
“We don’t always know exactly what the causal factors are biologically for an outcome we see, but cohort studies allow us to drill down into it in a way that most studies don’t allow you to do,” Geiger said.
Communicating risks
In the large research group at IKIDS, Geiger has led the report-back process for participating families. With grant funding, she helped pilot an app made for the task.
Collaborators at the Silent Spring Institute and UCSF created a smartphone-based tutorial for mothers who participated in two cohort studies, including IKIDS, that walked participants through their chemical exposure results and offered personalized recommendations for reducing contaminants in the future.
According to their study published this February, the tutorial helped study participants understand graphs that detailed their own chemical exposures, aimed at accessibility to participants of all education levels and backgrounds.
The digital interface showed participants how their own chemical exposure levels compared against other mothers collectively in both the study and nationally, then offered pointers to reduce exposure to endocrine-disrupting contaminants.
Some practical recommendations shared in the study: eating more fresh and frozen food, opting for drinks in glass bottles instead of cans, moisturizing with natural oils like shea butter or avoiding household products that are advertised as “antimicrobial.”
The tutorial proved effective at “creating intentions to adopt health-protective behaviors,” the study’s authors wrote, while providing a report-back tool that scaled for participants across different socioeconomic and educational backgrounds.
The tricky part, Geiger said, is framing risks in the proper dose. Since many of these chemicals are still being researched, investigators must give participants their best guidance off of incomplete or evolving information.
“We have to think really hard about how to report these levels back—it’s a little bit of a double-edged sword because we’re getting grants to study these chemicals simultaneously,” Geiger said. “It’s still emerging research with many of these chemicals, so we don’t always have that hard and fast guidance to give back.
“We’re continuing to do this work and hoping that, at the policy level, we become more aware that we may be doing damage to children at these crucial developmental stages, by dosing them with chemicals that are not tested or understood commensurate with the value that our children hold for the future.”
Editor’s note
To contact Sarah Geiger, email smurphy7@illinois.edu
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