New research suggests that babies born in Cincinnati during the mid-2000s were exposed to far more forever chemicals in the womb than scientists once believed.
The findings shine a spotlight on PFAS exposure during pregnancy and raise fresh questions about how these persistent chemicals may shape long-term health.
Per- and polyfluoroalkyl substances, commonly known as PFAS, are a large group of synthetic chemicals used for decades in everyday products. They are found in nonstick cookware, stain-resistant fabrics, food packaging, and firefighting foams.
Because they do not easily break down, they can linger in the environment and accumulate in the human body over time.
While researchers have studied a limited number of PFAS compounds for years, this new work suggests that the scope of prenatal exposure may be much broader than earlier testing methods revealed.
Mining archived samples for answers
The study was led by Shelley Liu at the Icahn School of Medicine at Mount Sinai. Her team analysed umbilical cord blood samples collected from 120 infants born between 2003 and 2006 as part of the HOME Study in Cincinnati.
By revisiting these archived samples nearly two decades later, researchers were able to apply newer laboratory techniques that were not available when the babies were born. This allowed them to build a more complete picture of cumulative PFAS exposure before birth.
Instead of testing only for a short list of well-known compounds, the team used a non-targeted chemical analysis approach. This method scans broadly for hundreds or even thousands of chemicals at once.
As a result, it captures compounds that traditional panels often miss, including newer or less-studied PFAS.
42 PFAS detected in cord blood
The results were striking. Researchers identified 42 confirmed or suspected PFAS compounds in umbilical cord blood samples. Many of these chemicals are rarely included in standard testing and have not been thoroughly evaluated for health effects.
The detected compounds spanned several PFAS subclasses, including perfluorinated and polyfluorinated chemicals and fluorotelomers. Together, they point to widespread prenatal PFAS exposure across multiple chemical types.
To make sense of this complex mixture, the team developed what they call PFAS-omics burden scores. Using item response theory, they developed a summary measure of a newborn’s total PFAS exposure at birth. Rather than focusing on one or two chemicals, the score captures the combined burden.
This broader lens also changed some assumptions. Earlier research, using narrower testing panels, suggested that first-born children might have different PFAS levels compared to siblings.
With the more comprehensive analysis, those differences were no longer apparent, underscoring how measurement methods can shape scientific conclusions.
Why prenatal PFAS exposure is so dangerous
Pregnancy is a particularly sensitive window for environmental exposures. Previous studies have linked prenatal PFAS exposure to outcomes such as lower birth weight, preterm birth, shifts in immune function, and metabolic changes. Some research has also suggested effects on how children respond to vaccines.
The new findings suggest that these earlier studies may have underestimated the true breadth of fetal exposure. If babies are encountering dozens of PFAS compounds rather than a handful, researchers may need to rethink how cumulative exposure influences development.
Professional groups have already raised awareness of the issue. The American College of Obstetricians and Gynecologists has identified reducing exposure to toxic environmental chemicals, including PFAS, as an important area for prevention efforts.
What this means for clinical care
Despite mounting evidence about potential health risks, PFAS exposure is not routinely measured in medical practice. There is currently no standard screening test used during pregnancy or early childhood.
The burden scoring method introduced in this study offers a possible path forward. In the future, similar tools could help identify individuals or communities with higher cumulative exposure.
That information might guide closer monitoring, targeted interventions, or policy changes aimed at prevention.
For now, the research primarily lays scientific groundwork. The children whose cord blood was analysed are now adolescents, providing a rare opportunity to study how early-life PFAS exposure may relate to health outcomes years later.
The next phase of research
The team plans to follow these participants to determine whether higher PFAS exposure at birth is associated with measurable health effects during adolescence. They also intend to investigate the newer, understudied PFAS compounds identified by the non-targeted approach.
As scientists refine tools to measure cumulative exposure more accurately, the conversation around PFAS exposure is likely to shift. What once appeared to be a limited set of chemicals may represent a far more complex mixture with implications that are only beginning to come into focus.
