Fetuses likely have more ‘forever chemicals’ in blood than thought – report

US test of 120 umbilical blood cord samples identified 42 Pfas compounds, which do not naturally break down

New peer-reviewed research shows fetuses likely have much higher levels of Pfas “forever chemicals” in their blood than previously thought.

Testing of umbilical cord blood typically looks for a small number of common Pfas compounds, like Pfoa and Pfos. However, thousands of Pfas exist, and a new Mount Sinai study tested 120 umbilical blood cord samples that were previously found to contain up to four compounds.

The expanded “non-targeted analysis” identified 42 Pfas compounds across the 120 samples, and the total level of Pfas in the blood was much higher than previously found.

The findings suggest “babies are exposed to many more Pfas than we previously thought”, said Shelley Liu, a study co-author and associate professor at the Icahn School of Medicine at Mount Sinai.

“It’s particularly important to understand because it is a very vulnerable period when fetuses are exposed,” Liu added.

Pfas are a class of about 15,000 compounds most frequently used to make products water-, stain- and grease-resistant. The chemicals have been linked to cancer, birth defects, decreased immunity, high cholesterol, kidney disease and a range of other serious health problems. They are dubbed “forever chemicals” because they do not naturally break down in the environment.

Fetuses are widely exposed to Pfas via umbilical cord blood. A review of 40 studies found researchers had collectively detected Pfas in each of 30,000 umbilical cord blood samples they checked. Elevated Pfas levels in mothers is associated with higher infant mortality, as well as low birth weight and obesity later in life. Studies have also linked fetal exposure to cancer, neurological problems and cardiovascular disease later in life.

The “legacy” compounds like Pfoa and Pfos were most commonly used until the last decade. Those have been phased out, and replaced with newer generations of Pfas that chemical makers claim, often without evidence, are less toxic. Meanwhile, Pfas may break down into new compounds once in the environment or human body.

Regulators’ methods to check blood, water and other mediums for these new Pfas have been slow in keeping up with the shift. The US Environmental Protection Agency, for example, typically only checks water samples using a test method that looks for around 30-40 compounds, though thousands have been found in water by independent researchers. A 2022 Guardian analysis found regulators frequently undercounted Pfas levels in water.

The Mount Sinai study effectively compared the umbilical cord blood samples using the old analysis and the broader “non-targeted” analysis that checks for thousands of compounds.

As expected, the more comprehensive testing found more Pfas, Liu said. The EPA recently certified a blood test that will check for 53 compounds. Liu said the expanded list is an improvement over the more limited tests, but Mount Sinai’s non-targeted analysis found 31 compounds not included in the EPA test.

Cover photo:  ‘Fetuses are widely exposed to Pfas via umbilical cord blood.’ Photograph: Olga Rolenko/Getty Images