Fluoride Exposure During Pregnancy May Increase Risk of Autism, ADHD and Other Neurobehavioral Side Effects: Study

Researchers called for more stringent limits and controls on the addition of fluoride to drinking water, which is a common practice to promote dental health.

A new study finds that prenatal fluoride exposure may increase the risk of children developing neurobehavioral problems, including autism and attention deficit hyperactivity disorder (ADHD).

Fluoride is a natural mineral found in water, soil, and certain foods, which is often added to drinking water and toothpaste to help prevent tooth decay by making teeth stronger, a well as decreasing rates of cavities.

In 2015, the U.S. Public Health Service set the optimal fluoride level in water at 0.7 milligrams per liter to protect teeth without causing stains. According to the U.S. Centers for Disease Control and Prevention (CDC), nearly two-thirds of people in the U.S. with access to public water are using fluoridated drinking water today. However, many consumers do not trust the addition of fluoride to their water supply, and have pushed back against the practice.

In a report published this week in the medical journal JAMA Network Open, researchers from the University of Florida and University of Southern California, Los Angeles warn that children residing in areas of the US with optimal fluoride levels may actually face a heightened risk of neurobehavioral issues, indicating that in utero exposure is likely a key component.

The study focused on Hispanic women in Los Angeles, using urine samples and neurobehavioral data collected between 2017 and 2023. Participants included individuals aged 18 or older, who were fluent in English or Spanish, providing urine samples during their third trimester of pregnancy, averaging 31.6 weeks gestation.

Researchers reviewed data on 229 mother-child pairs, with mothers averaging 29.45 years old. Of these pairs, 50.7% were female children and 49.3% were male children. Neurobehavior was assessed using the Preschool Child Behavior Checklist (CBCL), when children were around 36 months old. This checklist includes 99 items rated by mothers, measuring Total Problems, Internalizing Problems, and Externalizing Problems. Scores range from 28 to 100, with scores above 63 indicating clinical levels.

The study revealed that prenatal fluoride exposure is associated with increased neurobehavioral risks in US children, including depression, anxiety, problems with authority, autism and ADHD. Median MUFSG (a fluoride measure) was 0.76 mg/L, with scores ranging from 0.51 to 1.19 mg/L. An increase of just .68 mg/L of fluoride was linked to nearly double the risk of neurobehavioral problems, the researchers determined.

These behaviors can reduce quality of life for the child, negatively impacting their education and futures. They also often require additional education resources, and often involve medications that come with their own side effects, including the risk of misuse and addiction.

A study published in JAMA last year found that many high school students abuse Adderall, Ritalin and Vyvanse; drugs commonly prescribed to children with ADHD and autism.

“This cohort study found that prenatal fluoride exposure was associated with increased risk for neurobehavioral problems among children residing in the US,” the researchers concluded. “These findings suggest that there may be a need to establish recommendations for limiting exposure to fluoride from all sources during the prenatal period, a time when the developing brain is known to be especially vulnerable to injury from environmental insults.”