Fluoride exposure during pregnancy has been linked to an increased risk of childhood behavioral problems, according to research published today by the Keck School of Medicine of USC. Researchers at the university conducted the first U.S.

-based study examining the link between prenatal fluoride and childhood social, emotional and behavioral functioning. Nearly three-quarters of Americans consume drinking water that contains fluoride, a practice that began in 1945 to help prevent tooth decay, according to researchers. The findings appear in JAMA Network Open, a medical journal published by the American Medical Association.

The study analyzed more than 220 mother-child pairs, collecting data on fluoride levels during pregnancy and child behavior at age 3. The researchers found that a 0.68 milligram per liter increase in fluoride exposure was associated with nearly double the chance of a child showing neurobehavioral problems in a range considered close to or at a level to meet the criteria for clinical diagnosis.

“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 Tracy Bastain, an associate professor of clinical population and public health sciences at the Keck School of Medicine. The findings add to existing evidence from animal studies showing that fluoride can harm ne.