Environmental Contaminants Infiltrate Placenta during Pregnancy

Researchers at Karolinska Institutet (KI; Solna, Sweden), Rigshospitalet (Copenhagen, Denmark), and Copenhagen University (Denmark) conducted a study to measure the concentrations of distinct PFAS in human embryos and fetuses and corresponding placentas and maternal serum samples derived from elective pregnancy terminations and intrauterine fetal death cases. In all, 78 embryos and fetuses aged 7–42 gestational weeks were included for a total of 225 fetal organs, together with 71 placentas and 63 maternal serum samples. PFAS concentrations were assayed by liquid chromatography/triple quadrupole mass spectrometry.

The results revealed that PFAS concentrations in embryo/fetal tissue were lower than maternal serum, but similar to placenta concentrations. The total PFAS burden was highest in lung tissue in first trimester samples and in the liver in second and third trimester samples. The burden was lowest in CNS samples, irrespective of fetal age. The researchers found that placenta:maternal serum ratios increased across gestation, suggesting bioaccumulation in the placenta, and that the ratios were higher in pregnancies with male fetuses. The study was published on January 24, 2019, in Environment International.

“The main source of PFAS substances today is food, in the form of fish, milk, meat, and eggs, or in the drinking water, if you happen to live in a polluted area,” said senior author Pauliina Damdimopoulou, PhD, of the KI department of clinical science, intervention and technology. “We ingest them as a cocktail of substances that can also interact with each other. It would be in line with the precautionary principle in the restriction of chemical substances to make sure that all PFAS substances disappear from our society.”

The PFAS group comprises thousands of human-made chemicals with alkyl chains in which fluoride atoms replace hydrogen atoms, forming strong carbon fluorine bonds resistant to degradation. Thanks to their water- and grease-resistant properties, they are used in everything from frying pans and food packaging to clothes, cleaning agents, and firefighting foams. Many PFAS are regulated due to their bioaccumulative properties and toxicity for reproduction, and one, perfluorooctanesulfonic acid (PFOS) was banned by the European Union in 2008.

Related Links:
Karolinska Institutet
Rigshospitalet
Copenhagen University