Adding to the mounting body of evidence pointing to the health harms of exposure to per- and polyfluoroalkyl substances (PFAS), a new study published in Lancet Planetary Health by researchers at Aberdeen and Örebro Universities indicates that the “forever chemicals” affect humans as early as in the fetal stage of development.

PFAS have been used in consumer goods like nonstick cookware and food packaging since the 1950s, and in the present day, the chemicals are found increasingly in water, soil, food, and the human body due to their inability to break down. Their use has come under scrutiny in recent years as the body of scientific literature evidencing the chemicals’ association with cancer, diabetes, and a number of other diseases begins to grow.

For example, in December 2023, the World Health Organization’s International Agency for Research on Cancer (WHO’s IARC) classified two important classes of PFAS as carcinogenic, and noted that the general population is most at risk of exposure to the chemicals through their diet. Additionally, in November 2023, a U.S. National Institutes of Health (NIH) study provided strong evidence linking the ingestion of PFAS to thyroid cancer, and warned that there is no end in sight to the ubiquitous presence of the forever chemicals in food and the environment.

In the new study, a team of researchers from Örebro University and the University of Aberdeen conducted the first extensive metabolic profiling and measurement of PFAS in 78 human fetuses. The chemicals were detected in the livers of the fetuses. The results strongly suggest that exposure to PFAS in the womb affects unborn children, with altered metabolic and liver function observed in those exposed to higher levels of PFAS. Specifically, modified bile acid and lipid metabolism was noted. It is possible that these effects could persist and increase the risk of metabolic diseases in adulthood.

The researchers warn that changes in the central metabolism greatly affects the entire body, and that changes in fetal development can have long-lasting consequences for future health. The impact of pre-birth PFAS exposure is likely similar to changes that occur as a result of metabolic diseases like diabetes and fatty liver. Based on the fact that countries in which PFAS are very loosely regulated are experiencing heightened levels of childhood obesity and diabetes, such as China, in comparison to regions with more stringent regulations, such as the EU, the scientists hypothesize that exposure to PFAS and environmental chemicals may be one of the causes of this increase in childhood metabolic diseases.