New research has made a striking link between a mother’s exposure to “forever chemicals” during pregnancy and the shape of her child’s brain at age five. The findings offer no conclusion as to whether these brain changes are positive or negative, but simply suggest the chemical exposure is likely making some kind of impact on neural development.
“I think our results are interesting because of the clear associations between these chemicals during pregnancy and brain structural development in children," said the study co-author Aaron Barron, in an email to New Atlas. "It seems that even at low levels, chronic exposure to these chemicals might influence the brain.”
Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are persistent chemical pollutants with extremely long half-lives in humans. PFAS have widespread use and are present everywhere, from firefighting foams and cosmetics to kitchenware. This means most human beings living in the Western world are likely to have been chronically exposed to these chemicals over several years.
While forever chemicals are linked to various health issues, it is unclear whether they impact perinatal or childhood brain development. To understand the connection between maternal PFAS and brain structure, Barron and his colleagues measured PFAS compounds in blood samples taken from more than 50 pregnant mothers around week 24 of pregnancy. Five years later, when their children returned for a follow-up, the team used advanced MRI techniques and captured detailed views of brain structure, white matter pathways, and connectivity of different brain regions.
The team found that various PFAS compounds each had their own unique effect on the brain, with no differences between boys and girls.
“Different PFAS seem to be associated with different parts of the brain, and in a few cases, different PFAS even had opposite associations with the same brain region,” Barron told New Atlas.
A mother's PFAS were associated with many aspects of their children’s brain structure, but three main areas particularly stood out. These were: the corpus callosum, the brain's largest white matter tract that connects the two hemispheres of the brain; the occipital cortex, responsible for vision and visual processing; and the hypothalamus, which regulates hormone levels and metabolism.
Importantly, the study was a population-based cohort, so it did not include individuals with extremely high exposure, such as PFAS factory workers or firefighters. Although most of the mothers in the study had measurable PFAS in their blood, the levels were not especially high.
“But even at these low levels, PFAS were strongly and linearly associated with brain structure – which means that the potential effects of PFAS on brain development are not only relevant for the minority of the population with very high PFAS exposure, but for everyone,” Barron explained.
Barron says that, unlike something like exercise, smoking, or alcohol consumption, there is no immediate lifestyle change that can rapidly reduce the concentration of these chemicals in your blood during pregnancy. In the short term we do know it is possible to reduce PFAS exposure by checking PFAS levels in your local water supply, generally limiting seafood consumption, or avoiding high-PFAS clothing and cosmetic products.
“At the moment, it is unclear whether PFAS are directly affecting brain development, although it’s known that they pass the placenta and the blood-brain barrier to accumulate in the brain, and can disturb developing brain cells," said Hasse Karlsson. another co-author on the new study. "It’s also unclear whether these associations are harmful, beneficial, or neutral, and future studies will be needed to determine the functional implications of our findings.”
Barron also emphasized his team's findings are not cause for immediate concern.
“I would hesitate to jump to any conclusions, and I don't think any expecting mother should worry right now," he told New Atlas. "These chemicals are present in every mother's blood. Unless you may be near a site of extremely high PFAS exposure, worrying about chemical exposure can cause a lot of stress, which can itself be quite detrimental for the developing baby.”
The study has been published in The Lancet Planetary Health.
Source: University of Turku
