Babies born between 2003 and 2006 were exposed in the womb to a broader mix of per- and polyfluoroalkyl substances (PFAS) than standard tests typically capture, according to a new peer-reviewed study that used non-targeted chemical screening on umbilical cord blood and detected 42 confirmed or putatively identified PFAS compounds.
Researchers from the Icahn School of Medicine at Mount Sinai report that archived umbilical cord blood samples from 120 infants in the Cincinnati-based HOME (Health Outcomes and Measures of the Environment) Study contained a far wider range of PFAS—often called “forever chemicals”—than is usually measured in conventional laboratory panels.
The study, published in Environmental Science & Technology, was led by Shelley H. Liu, PhD, an Associate Professor of Population Health Science and Policy at Mount Sinai. The team analyzed stored cord blood collected at birth between 2003 and 2006, a time frame that allows the researchers to potentially link prenatal exposure patterns with health outcomes as the children are now adolescents.
Instead of relying on targeted testing that looks for a short, predefined list of well-known PFAS, the researchers used a non-targeted chemical analysis approach designed to scan for hundreds to thousands of chemicals simultaneously. Using this broader screening method, they identified 42 PFAS that were either confirmed or putatively identified in cord blood. The detected compounds included perfluorinated chemicals, polyfluorinated chemicals, and fluorotelomers—categories that encompass many substances not routinely included in standard PFAS tests.
To summarize overall prenatal exposure, the researchers developed what they call “PFAS-omics burden scores,” using item response theory methods to create a composite measure intended to represent a newborn’s total PFAS exposure at a single point in time.
Using this more comprehensive scoring approach, the team reported that they did not observe differences in overall PFAS exposure between babies born to first-time mothers and those born to mothers with prior pregnancies—an association that earlier studies using narrower PFAS panels had reported.
“Our findings suggest that how we measure PFAS really matters,” Liu said. “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.”
The researchers noted that pregnancy is a sensitive developmental window and that prior research has linked prenatal PFAS exposure to outcomes including low birth weight, preterm birth, altered immune responses to vaccines, and metabolic changes.
“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.”
The American College of Obstetricians and Gynecologists has identified reducing exposure to toxic environmental chemicals such as PFAS as a “critical area of intervention,” according to the research briefing.
The work was funded by the U.S. National Institutes of Health, and the research briefing listed collaborating institutions including the University of Michigan and the University of Cincinnati, among others. The team said future research will examine whether higher cumulative PFAS exposure early in life is associated with later health outcomes and will further investigate the newly detected and understudied PFAS found in cord blood.
