• Posted August 19, 2026

Study Raises New Questions About Fluoride Exposure During Pregnancy

A new study funded by the National Institutes of Health is raising questions about fluoride exposure during pregnancy and children's cognitive development.

"This study addresses an important gap by evaluating prenatal water fluoride and child cognition in a large U.S. sample," said lead author Katrina Simon of the Columbia University Mailman School of Public Health. 

"Findings from this work offer evidence that can inform ongoing guidance aimed at supporting children's development," she added in a news release.

Researchers compared test scores from more than 2,500 children between the ages of 3 and 17 with prenatal fluoride exposure estimated from public drinking water levels where their mothers lived.

Fluoride levels near or above 675 micrograms per liter were associated with significantly lower scores on tests of fluid cognition, including problem-solving, memory, attention and adapting to new information. 

The link appeared stronger in children under age 7.

The U.S. Public Health Service recommends no more than 700 micrograms of fluoride per liter in community drinking water. The EPA's regulatory limit is higher, at 4,000 micrograms per liter.

This was an observational study, so it cannot prove that fluoride caused the differences. 

Researchers only estimated fluoride exposure from public drinking water — not total exposure, including other sources like toothpaste, food, supplements or bottled water.

"This study adds to a large body of work that looks at how early exposure to environmental contaminants may be associated with the development of the thinking and learning processes that are important for children's developmental outcomes," said co-senior author Amy Margolis of Ohio State University Wexner Medical Center and College of Medicine. 

"Continuing to study fluoride and other exposures will be integral in best supporting children's environmental health and well-being," she added in a news relase.

The findings were recently published in the American Journal of Epidemiology.

More information

The Cleveland Clinic has more on fluoride.

SOURCE: HealthDay TV, Aug. 19, 2026