Babies are exposed to more 'forever chemicals' before birth than previously known

Analysis of umbilical cord blood from babies born between 2003 and 2006 detected 42 distinct PFAS compounds, many of which are not routinely screened. This broader, non-targeted approach revealed that prenatal exposure to PFAS is more extensive and complex than previously recognized, underscoring the need for improved assessment methods to better understand and mitigate potential health risks.

Babies born in the early 21st century were exposed to many more "forever chemicals" before birth than scientists previously understood, according to new research published in Environmental Science & Technology.
Thousands of these chemicals, known as per- and polyfluoroalkyl substances or PFAS, remain in use today, and their human health effects are poorly understood—making it crucial to better understand cumulative PFAS exposure in utero.
PFAS are a large class of man-made chemicals used in products such as nonstick cookware, stain-resistant fabrics, food packaging, and firefighting foams. They are often called "forever chemicals" because they persist in the environment and the human body.
The researchers measured PFAS in archived umbilical cord blood samples collected between 2003 and 2006 from 120 babies.
Looking back two decades allowed the researchers to create a new tool that can be linked to health outcomes in the now-adolescent study participants, which will be a focus of future research.

Using a newer, non-targeted chemical analysis method—a technique that scans for hundreds to thousands of chemicals at the same time rather than testing for a short, predefined list—the research team detected many more PFAS chemicals in umbilical cord blood than traditional testing methods capture, including newer and understudied compounds.
The researchers found 42 confirmed or putatively identified PFAS chemicals in cord blood using this non-targeted approach. Many of these PFAS are not commonly screened by traditional testing methods and their health effects are unknown.

The results showed that infants are exposed to a wide range of PFAS, including perfluorinated chemicals, polyfluorinated chemicals, and fluorotelomers, before birth.

The researchers created PFAS-omics burden scores, using item response theory methods, to summarize total exposure to PFAS. The PFAS-omics scores can be interpreted as a snapshot in time of a baby's overall PFAS exposure.

Importantly, when researchers used this broader PFAS assessment, they did not observe exposure differences between babies born to first-time mothers and those born to mothers with previous pregnancies—a difference that earlier studies had reported using more limited PFAS panels.

Pregnancy is a period of heightened vulnerability. Previous research has linked prenatal PFAS exposure to low birth weight, preterm birth, altered immune responses to vaccines, metabolic changes, and other developmental concerns.

Quantifying PFAS-omics burden scores for non-targeted analysis using multi-dimensional item response theory: An exploratory analysis of novel and legacy PFAS in cord blood ., Environmental Science & Technology (2026). DOI: 10.1021/acs.est.5c06490