Fluoride Exposure During Pregnancy Linked to Behavior Problems in Kids

Summary: A new study finds that higher fluoride levels in pregnant women are associated with increased odds of their children experiencing neurobehavioral problems at age 3.

These problems include anxiety, difficulty regulating emotions, and physical complaints like stomachaches and headaches. Researchers urge policymakers to consider these findings and create specific recommendations for fluoride consumption during pregnancy.

Key Facts:

  • Increased fluoride in pregnant women’s urine is linked to double the odds of neurobehavioral issues in children.
  • The study is the first U.S.-based research on this topic.
  • There’s no known benefit of fluoride for developing fetuses.

Source: University of Florida

Higher fluoride levels in pregnant women are linked to increased odds of their children exhibiting neurobehavioral problems at age 3, according to a new study led by a University of Florida College of Public Health and Health Professions researcher.

The findings, based on an analysis involving 229 mother-child pairs living in a U.S. community with typical fluoride exposure levels for pregnant women in fluoridated regions in North America, appear May 20 in the journal JAMA Network Open.

This shows a pregnant woman drinking water.
The investigators found that women with higher fluoride exposure during pregnancy tended to rate their children higher for overall neurobehavioral problems. Credit: Neuroscience News

It is believed to be the first U.S.-based study to examine associations of prenatal fluoride exposure with parent-reported child neurobehavioral issues, which include symptoms of anxiety, difficulty regulating emotions and other complaints, such as stomachaches and headaches.

Fluoride, a mineral, has been added to community water supplies since the 1940s as a way to reduce dental cavities in children and adults. Nearly three-quarters of the U.S. population receives fluoridated tap water. The impacts of fluoride on human health, both positive and negative, have been the subject of much recent debate and ongoing scientific scrutiny.

The study’s lead investigator Ashley Malin, Ph.D., an assistant professor in the department of epidemiology in the UF College of Public Health and Health Professions and UF College of Medicine, said that taken with other recent studies conducted in Canada and Mexico on the effects of fluoride on young children’s IQ, the findings suggest fluoride may negatively affect fetal brain development.

“There is no known benefit of fluoride consumption to the developing fetus,” Malin said, “but we do know that there is possibly a risk to their developing brain.

“We found that each 0.68 milligram per liter increase in fluoride levels in the pregnant women’s urine was associated with nearly double the odds of children scoring in the clinical or borderline clinical range for neurobehavioral problems at age 3, based on their mother’s reporting.”

The fluoride levels found in the study participants’ samples are typical for people living in communities with fluoridated water, the researchers say. However, according to the paper, authors do not know whether findings observed in this study are generalizable to other U.S. populations or are nationally representative and therefore more research is required to address that question.

Individual differences in a person’s fluoride exposure can be attributed to variances in dietary consumption, such as drinking and cooking with tap water versus filtered water, or consuming food and drinks naturally high in fluoride, including green and black tea, certain seafoods and foods sprayed with fluoride-containing pesticides.

For the new study, investigators used data from the Maternal and Developmental Risks from Environmental and Social Stressors, or MADRES, study conducted at the Keck School of Medicine of USC. MADRES is led by Tracy Bastain, Ph.D., the senior author of the current fluoride study and an associate professor of clinical population and public health sciences, and Carrie Breton, Sc.D., a professor of population and public health sciences. The MADRES study follows a group of predominantly Hispanic women with low-income and their children living in Los Angeles County from pregnancy through childhood.

Researchers collected urine samples from MADRES participants during their third trimester of pregnancy. Urinary fluoride is the most widely used measure of individual fluoride exposure in epidemiological studies, including those assessing effects on fetal brain development.

Because fluoride, when combined with disinfecting agents, may cause lead to leach from lead-bearing water pipes, the scientists conducted various analyses to be sure any neurobehavioral effects could not be attributed to lead.

When their children reached age 3, study mothers completed the Preschool Child Behavior Checklist, which assesses children’s behavior and emotions. The investigators found that women with higher fluoride exposure during pregnancy tended to rate their children higher for overall neurobehavioral problems.

The study team hopes their findings spur policymakers to create specific recommendations for fluoride consumption during pregnancy.

“I think this is important evidence, given that it’s the first U.S.-based study and findings are quite consistent with the other studies published in North America with comparable fluoride exposure levels,” Malin said.

“Conducting a nationwide U.S. study on this topic would be important, but I think the findings of the current study and recent studies from Canada and Mexico suggest that there is a real concern here.”

Malin’s research is supported by the National Institute of Environmental Health Sciences of the National Institutes of Health.

Funding: The MADRES study is funded by the Environmental Protection Agency.

About this neurodevelopment and behavior research news

Author: Eric Hamilton
Source: University of Florida
Contact: Eric Hamilton – University of Florida
Image: The image is credited to Neuroscience News

Original Research: Open access.
Maternal Urinary Fluoride and Child Neurobehavior at Age 36 Months” by Ashley Malin et l. JAMA Network Open


Maternal Urinary Fluoride and Child Neurobehavior at Age 36 Months


Recent studies in Canadian and Mexican populations suggest an association of higher prenatal fluoride exposure with poorer neurobehavioral development, but whether this association holds for US-based populations is unknown.


To examine associations of third trimester maternal urinary fluoride (MUF) with child neurobehavior at age 3 years in the US.

Design, Setting, and Participants  

This prospective cohort study utilized urine samples archived from 2017 to 2020 and neurobehavioral data assessed from 2020 to 2023 from the Maternal and Developmental Risks from Environmental and Social Stressors (MADRES) pregnancy cohort, which consisted of predominately Hispanic women residing in Los Angeles, California. Cohort eligibility criteria at recruitment included being 18 years of age or older, less than 30 weeks’ gestation, and a fluent English or Spanish speaker.

Exclusion criteria included having a disability preventing participation or provision of informed consent, being HIV positive or incarcerated, and having a multiple gestation pregnancy. There were 263 mother-child pairs who completed the 3-year study visit. In this analysis, women who reported prenatal smoking were excluded. Data analysis was conducted from October 2022 to March 2024.


Specific gravity-adjusted MUF (MUFSG), a biomarker of prenatal fluoride exposure.

Main Outcomes and Measures  

Neurobehavior was quantified using the Preschool Child Behavior Checklist (CBCL), which included composite scores for Total Problems, Internalizing Problems, and Externalizing Problems. CBCL composite T scores range from 28 to 100. T scores from 60 to 63 are in the borderline clinical range, whereas scores above 63 are in the clinical range. Linear and logistic regression models adjusted for covariates were conducted.


A total of 229 mother-child pairs (mean [SD] maternal age, 29.45 [5.67] years; 116 female children [50.7%] and 113 male children [49.3%]) who had MUFSG measured were included in the study. Median (IQR) MUFSG was 0.76 (0.51-1.19) mg/L, and 32 participants (14.0%) had a Total Problems T score in the borderline clinical or clinical range. A 1-IQR (0.68 mg/L) increase in MUFSG was associated with nearly double the odds of the Total Problems T score being in the borderline clinical or clinical range (odds ratio, 1.83; 95% CI, 1.17-2.86; P = .008), as well as with a 2.29-point increase in T score for the Internalizing Problems composite (B = 2.29; 95% CI, 0.47-4.11; P = .01) and a 2.14-point increase in T score for the Total Problems composite (B = 2.14; 95% CI, 0.29-3.98; P = .02).

Conclusions and Relevance  

In this prospective cohort study of mother-child pairs in Los Angeles, California, prenatal fluoride exposure was associated with increased neurobehavioral problems. These findings suggest that there may be a need to establish recommendations for limiting fluoride exposure during the prenatal period.

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