Babies are entering the world with a significantly higher chemical burden than scientists suspected.

Using advanced data science and chemical detection, researchers have discovered that newborns are exposed to a much broader array of "forever chemicals" before birth than earlier testing methods could capture. 

The findings — from the Icahn School of Medicine at Mount Sinai in New York City — were published Feb. 18 in Environmental Science & Technology.

These substances, known as perfluoroalkyl and polyfluoroalkyl substances (PFAS), are created chemicals used in everyday items like nonstick pans, stain-resistant rugs and food wrappers.

They’re often called "forever chemicals," because they do not break down easily in the environment or the human body.

For the study, researchers used a broad, cutting-edge analysis to scan umbilical cord blood samples from 120 babies born between 2003 and 2006 in Cincinnati, Ohio. 

Unlike traditional tests that look for a specific, short list of known chemicals, this new method scans for thousands of substances at once.

The results were eye-opening. 

Researchers identified 42 types of PFAS in the cord blood, including many newer compounds that are poorly understood and rarely screened. 

Before they were born, babies in the study had been exposed to a wide range of PFAS, including perfluorinated chemicals, polyfluorinated chemicals and fluorotelomers.

This suggests that prenatal exposure is far more complex than scientists realized 20 years ago.

“Our findings suggest that how we measure PFAS really matters,” lead author Shelley Liu, an associate professor at Mount Sinai, said in a news release. 

“When we look more comprehensively, we see that babies are exposed to far more PFAS chemicals before birth than we previously realized — and some of the patterns we thought we understood may change,” she added.

This early exposure is a concern as pregnancy is a critical window for development. 

Previous studies have linked PFAS exposure to several health concerns, including lower birth weights, preterm births and even weakened immune responses to childhood vaccines, researchers noted. 

By identifying the true scale of the PFAS burden, researchers hope to better understand how these chemicals affect children as they grow into adolescence.

“Our study helps show that prenatal PFAS exposure is more complex and widespread than earlier studies suggested,” Liu said. “Understanding the full picture is essential if we want to protect child health and reduce preventable environmental risks.”

Doctors do not routinely test for PFAS during pregnancy. 

But the American College of Obstetricians and Gynecologists has for years called reduction of toxic environmental exposures a major priority for maternal health.

This foundational research could help pave the way for clinicians to measure more broadly and pinpoint at-risk populations and strategies to reduce exposure.