Most expectant mothers are careful to protect their developing child during pregnancy but new research from Yale University suggests there may be a hidden dangers lurking. Data suggests exposure to synthetic chemicals commonly used in food packaging and elsewhere may increase a woman’s risk for miscarriage in the second trimester.

All 440 women in the study had some levels of different types of per- and polyfluoroalkyl substances (PFAS) in their pregnancy serum and those with the highest levels of two common varieties had between an 80 percent and 120 percent increase in the likelihood of a miscarriage compared to those with the lowest levels. There were other positive associations but they were less consistent and at smaller magnitudes for exposure to other less common types of PFAS.

It is estimated between 10 and 20 percent of all pregnancies end in miscarriage.

Previous studies in rodents found high levels of PFAS exposure was linked to pregnancy loss. This study compared 220 women in Denmark who carried their baby full term to 220 women who experienced a miscarriage in the second trimester. The findings published in the journal Environmental Health Perspectives showed the association was stronger for women who had previously given birth.

PFAS have been around since the 1940s and are widely used in industries such as aerospace, automotive, construction, electronics and the military. They can be found in products such as cookware, clothing, carpets and firefighting foam. PFAS usage in commercial products is not currently regulated in the U.S. but some common types have been phased out by manufacturers because of impact concerns on human health and the environment. However, other compounds in the PFAS family have taken their place.

"Policy regulation of PFAS exposure should consider adverse effects on maternal and child health, which have repeatedly suggested that these are vulnerable populations that need to be protected from exposure to these widespread chemicals," said Zeyan Liew, the study's lead author and an assistant professor in the department of Environmental Health Sciences at the Yale School of Public Health. "More studies should follow up to investigate whether PFAS, widespread pollutants that are affecting nearly all pregnancies in the general population, are a modifiable risk factor for miscarriage."

Serum samples were taken at around the eight-week mark of gestation and were measured for several common PFAS compounds. It is believed the PFAS exposure in Denmark is similar to that experienced by the U.S. population.

"Mechanistic studies are needed to elucidate the possible biological mechanisms that explain these associations," Liew said. "Moreover, larger epidemiological studies are needed to replicate our findings, evaluate the possible threshold or dose-dependent effects of PFAS exposure on pregnancy loss, and address confounding by pregnancy history."

Click here to read more in Environmental Health Perspectives.