Maternal 'Forever Chemicals' Linked to Differences in 5-Year-Olds' Brain Structure and Connectivity

New Finnish study links maternal PFAS levels during pregnancy to measurable differences in children's brains

Researchers in Finland report that concentrations of per- and polyfluoroalkyl substances (PFAS) measured in mothers' blood during pregnancy were associated with structural and connectivity differences in their children's brains at age five. The study, led by the University of Turku and published in The Lancet Planetary Health, compared prenatal PFAS measurements with multimodal magnetic resonance imaging (MRI) of the children.

What are PFAS?

PFAS—often called "forever chemicals"—are a large family of synthetic compounds used to make materials resistant to water, oil, heat and electrical conduction. They are found in some nonstick cookware, stain-resistant fabrics, food packaging, firefighting foams and other consumer and industrial products. PFAS are persistent in the environment and do not readily biodegrade.

Study design and key findings

In this investigation, maternal blood samples collected during pregnancy were analyzed for PFAS concentrations at Örebro University (Sweden). The children—all aged five—underwent multimodal MRI at Turku University Hospital. The final analysis included 51 mother–child pairs.

Investigators reported associations between higher maternal PFAS levels and differences in several brain regions of their children, notably the corpus callosum, occipital lobe and hypothalamus. Some PFAS compounds were linked both to structural differences and to altered functional connectivity on MRI, which suggests potential changes in how brain regions communicate. The observed associations were similar for boys and girls.

Interpretation and limitations

"Humans consume PFAS from drinking water, food, or in some cases occupational exposure. They are ubiquitous in our blood, and our bodies do not break them down," said Aaron Baron, the study's lead author and senior researcher at the University of Turku.

The authors and outside experts emphasize caution in interpreting these findings. The sample size was small (51 pairs), and the study shows associations rather than proof of causation. While experimental and biomonitoring data indicate that some PFAS cross the placenta and can accumulate in brain tissue, it remains unclear whether the brain differences observed are harmful, neutral, or—less likely—beneficial. The researchers call for larger longitudinal studies to determine functional and developmental implications.

Public health context and actions

Over the past decade, higher PFAS blood concentrations have been linked to disruptions in hormone synthesis, metabolism and immune function, prompting regulatory and industry responses. The U.S. Environmental Protection Agency has proposed stricter limits for certain PFAS in drinking water, and several states have restricted PFAS in products such as cosmetics, food wrappers and firefighting foam.

Scientists are also investigating remediation methods—including advanced filtration and biological approaches—to remove PFAS from water and soil.

How individuals can reduce exposure

• Avoid nonstick cookware and replace heavily stain-resistant fabrics when possible.
• Limit consumption of foods that may contain PFAS from packaging (e.g., some fast-food wrappers) and follow local guidance on contaminated water.
• Support companies and policies that phase out PFAS and adopt PFAS-free alternatives.

Bottom line: This study adds to growing evidence that prenatal PFAS exposure may be associated with measurable differences in early childhood brain structure and connectivity, but it does not establish causation. Larger, follow-up studies are needed to clarify whether these brain differences translate to meaningful effects on development or behavior.

For updates on environmental health research and practical steps to reduce exposure, consider following reputable public health sources and peer-reviewed literature.