The placenta does not protect your foetus against fluorinated substances

​Researchers from Rigshospitalet have discovered that, throughout pregnancy, foetuses are exposed to fluorinated substances that accumulate in their lungs and livers. These recently published results have raised concern for researchers.
In a recently published study in Environment International, researchers from the Laboratory of Reproductive Biology at Rigshospitalet show how fluorinated substances, which are used in many consumer products, pass through the placenta to accumulate in the vital organs of the foetus. Whether the substances affect foetal development is not yet clear.

Products containing fluorinated substances include pizza boxes, baking paper, packaging for microwave popcorn and winter boots. Fluorinated substances are used in many products, as they make the surface water-and-grease repellent and this makes many things in life much easier. However, some of these substances have proven to be carcinogenic and endocrine disrupting and may have a negative effect on reproductive health. The substances are also suspected of having an impact on human embryonic and foetal development.  

"We've examined six of the most controversial perfluoroalkylated substances (PFAS) and found that they all appear to the same extent in foetal organs as in the placenta," said Linn Salto Mamsen, a postdoc at the Laboratory of Reproductive Biology at Rigshospitalet and one of the authors of the study. 

A new study shows that newborns already have a build-up of PFAS in their lungs and liver. Photo: Linn Salto Mamsen

This means that when the baby is born, it already has a build-up of these slowly degrading substances," she explained and continued: "It’s worrying that in some cases PFAS levels are as high as in adults.

"It’s worrying that in some cases PFAS levels are as high as in adults," said Linn Salto Mamsen in the photo. Photo: Vertan Epremian

Levels were highest in the lungs and in the liver

The PFAS levels were highest in the lung and liver tissue, in some cases as high as in adults. The lowest levels were found in the brain. PFAS also accumulate in adult organs, mainly in the lungs, liver and kidneys. "We can now see this accumulation in the organs of foetuses," explained Linn Salto Mamsen. 

Male foetuses are more exposed than female foetuses

The study found that the accumulation of PFAS was higher in male foetuses than female. Adult males generally also have higher levels of PFAS than adult females. Studies in mice show that male mice do not metabolise perfluorinated compounds as effectively as female mice. If this applies for humans, this may explain the higher levels in boys. 

"Previous studies have shown a correlation between the mother's level of PFAS and low birth weight of the child – a tendency that is most pronounced in newborn boys, indicating that perhaps boys are more sensitive to chemicals than girls," explained Linn Salto Mamsen.  

Need for greater focus on the use of PFAS

The study included tissue from 78 embryos and foetuses aged 7 to 42 gestational weeks from both Denmark and Sweden. Among the six substances studied, PFOS and PFOA are the best known. PFOS was banned by the EU in 2008, and in early 2018 the European Food Safety Authority lowered the tolerable daily intake by a thousandfold. This shows an increased focus on these substances, and the importance of research in this area. 

"Today the tolerable daily intake of PFAS is determined on the basis of studies on mice and observed levels in adults. We don't actually know how much or how little it takes to harm foetal development. We need more studies to clarify this," explained Linn Salto Mamsen.

Absorbed through food

PFAS have been used for decades and are ubiquitous in our environment. "We primarily absorb PFAS through our food. These substances are very persistent and accumulate in both our environment and our organisms. They are found particularly in fish, meat and dairy products, and vegetables, and, as I mentioned before, also in food packaging, so they can be difficult to avoid as a consumer," Linn Salto Mamsen continued.  

Advice for pregnant women

Based on her knowledge as a researcher and the new publication, Linn Salto Mamsen has the following advice for pregnant women:

"If you're pregnant, you should try reducing your intake of PFAS, for example by putting your pizza on a plate instead of eating it directly from the box. Use sandwich paper and baking paper with the Nordic Ecolabel as this will not contain fluorinated substances. Eat stovetop popcorn instead of microwave popcorn.  Use ceramic cookware instead of teflon. Buy products with long shelf life in glass instead of in plastic or metal cans," said Linn Salto Mamsen.   

About the study

The study was conducted in cooperation between researchers from Rigshospitalet, Karolinska Instituttet in Stockholm and the University of Lund.  The study was funded by the inter-regional EU project ReproUnion, the Novo Nordisk Foundation, the Swedish Research Council and the Jane and Aatos Erkko Foundation.


The full publication is available on this link: 

Linn Salto Mamsen, Richelle D. Björvang, Daniel Mucs, Marie-Therese Vinnars, Nikos Papadogiannakise, Christian H. Lindh, Claus Yding Andersen and Pauliina Damdimopoulou. Environment International, online 24 January 2019, doi: 10.1016/j.envint.2019.01.010

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