• Posted May 21, 2024

For Pregnant Women, Fluoridated Drinking Water Might Raise Risks for Baby: Study

Fetal exposure to fluoride from a mom-to-be's drinking water might raise the odds for physical and mental health issues in toddlers, new research suggests.

The study, which was funded by the U.S. National Institutes of Health, wasn't designed to prove cause-and-effect. However, researchers believe the findings are worth investigating further.

“This is the first U.S.-based study to examine this association. Our findings are noteworthy, given that the women in this study were exposed to pretty low levels of fluoride -- levels that are typical of those living in fluoridated regions within North America,” said study lead author Ashley Malin, an assistant professor of epidemiology at the University of Florida. She conducted the research in part as a postdoctoral scholar at the Keck School of Medicine in Los Angeles.

No one is saying fluoridation needs to stop, however.

“I don’t think we’re at the point where we are saying that water should not be fluoridated. It’s generally considered one of the biggest public health wins, certainly for the dental community,” study co-author Tracy Bastain told NBC News.

“But our results do give me pause. Pregnant individuals should probably be drinking filtered water," added Bastain, an associate professor of clinical population and public health sciences at the Keck School of Medicine.

U.S. municipalities started adding fluoride to water supplies back in the 1940s, due to its proven effect in preventing cavities in children. Now, about three-quarters of Americans have fluoride in their tap water.

However, recent studies have suggested that drinking fluoridated water while pregnant might affect the fetus, Malin and colleagues noted.

The new research involved 29 mother-child pairs. Each mother's urine was sampled during the third trimester of pregnancy to gauge fluoride levels (samples were collected after fasting, to enhance accuracy).

When the offspring from those pregnancies reached the age of 3, they were each assessed using the Preschool Child Behavior Checklist. The checklist is based on parents' reporting of their toddler's social and emotional functioning.

Reporting May 20 in the journal JAMA Network Open, Malin's group found that children who'd been exposed to 0.68 milligrams per liter of fluoride in the womb were 1.83 times more likely to exhibit behavioral problems "considered to be clinically significant or borderline clinically significant," according to the researchers.

More specifically, these issues includes physical complaints like headaches and stomaches, or troubles such as "emotional reactivity" (emotional outbursts), anxiety and symptoms that might be linked to autism.

“It certainly doesn’t mean that the child has autism," Bastain told NBC News. "We don’t even have autism diagnosis information” for the children in the study, she noted.

The study found no link between fetal fluoride exposures and other behavioral issues, such as attention problems or aggression, Malin's team added.

The researchers noted that, as of now, there are no guidelines for women as to whether or not they should avoid fluoride during pregnancy.

Malin believes that might change after studies like this one.

“There are no known benefits to the fetus from ingesting fluoride,” Malin said in a Keck news release. “And yet now we have several studies conducted in North America suggesting that there may be a pretty significant risk to the developing brain during that time.”

Her team plans future research into how fluoride exposure in infancy might affect the developing brain, along with looking at regional variations in fluoride exposures and effects.

Dr. Mark Moss, division director of public health dentistry at the East Carolina University School of Dental Medicine in Greenville, N.C., told NBC News that the findings might “cause a stir,” but said no change to water systems is needed right now.

“This is something that deserves a further look,” said Moss, who was not involved in the new study. “But in terms of public health practice, no, this doesn’t rise to the level of hitting the pause button” on fluoridation.

More information

Find out about fluoride's effect on child dental health at the American Dental Association.

SOURCE: Keck School of Medicine, University of South California, news release, May 20, 2024; NBC News