Fluoride Exposure in the Womb Could Lead to Later Problems in Kids

New research could point to a hidden risk of fluoride in early development. The study found a link between higher fluoride exposure in pregnant women and a greater risk of their children later being diagnosed with neurobehavioral problems by age 3. The findings do not confirm a cause-and-effect link, but they do warrant further investigation, the study authors say.

The research was led by scientists at the University of Southern California’s Keck School of Medicine. They studied data from an existing project run by USC researchers at the Center for Environmental Health Disparities: the Maternal and Developmental Risks from Environmental and Social stressors (MADRES) study. As part of the MADRES study, researchers tracked the health of local mothers and their babies, starting in early pregnancy through the first years of childhood.

The study analyzed data from 229 pairs of mothers and children. The mothers’ level of fluoride exposure was estimated based on urine tests they took during the third trimester, while the children’s level of social and emotional functioning was measured via the Preschool Child Behavior Checklist, a test taken by the parents.

The team found a noticeable correlation between higher fluoride levels in moms and a greater prevalence of certain clinically significant behavioral problems in their children at age 3. Specifically, for each additional 0.68 milligrams per liter of fluoride exposure in the womb, the children were 1.83 times more likely to show potential behavioral issues. The findings are published Monday in the journal JAMA Network Open.

“Women with higher fluoride exposure levels in their bodies during pregnancy tended to rate their 3-year-old children higher on overall neurobehavioral problems and internalizing symptoms, including emotional reactivity, anxiety and somatic complaints,” said senior study author Tracy Bastain, an associate professor of clinical population and public health sciences at USC, in a statement from the university.

The results are based on a relatively small sample size, and population studies such as this one cannot prove a causal link. But some other research has found evidence that early fluoride exposure can harm neurodevelopment, at least in animals. And while this appears to be the first U.S. study of its kind, there have been similar studies in Mexico, Canada, and other countries suggesting the same connection, according to the team. Recent reviews have concluded that more rigorous studies are needed to settle this question.

Fluoride is important to our dental health, helping strengthen tooth enamel, which is why it’s been routinely added to drinking water for decades. In children and adults, water fluoridation is thought to prevent up to 25% of cavities. But the study authors note that there doesn’t seem to be any such health benefit for developing fetuses in the womb. And should research continue to suggest a possible harm from early fluoride exposure, they’re hopeful that it could lead to new public health recommendations that people limit fluoride while pregnant.

“While this is the first U.S.-based study of fluoride exposure during pregnancy, more studies are urgently needed to understand and mitigate the impacts in the entire U.S. population,” Bastain said. The team is next planning to study exactly how fluoride exposure might be affecting the development of children in the MADRES population.