Health & Science

Study: Drinking Fluoridated Water During Pregnancy May Contribute To Lower IQ In Offspring

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What if there was something that pregnant moms did regularly that could drastically reduce their unborn child’s IQ?

According to recent research from Canada, drinking fluoridated tap water during pregnancy may be associated with lower IQ scores in 3- and 4-year-old boys. More specifically, for every 1 milligram increase per liter of a mother’s urinary fluoride levels, the study showed a son’s IQ score dropped by about 4.5 points, and an average of 3.7 when accounting for both boys and girls. This is on par with the other recent studies looking at childhood IQ and low-level lead exposure.

“Fluoride crosses the placenta,” the researchers explained, “and laboratory studies show that it accumulates in brain regions involved in learning and memory and alters proteins and neurotransmitters in the central nervous system.”

Fluoride was added to drinking water in the 1950s to help prevent cavities, leading public health and government officials to say it reduced their prevalence by a whopping 60 percent.  At one point it was hailed by the Centers for Disease Control and Prevention as one of public health’s greatest success stories. Today over two-thirds of the population in the United States receives fluoridated tap water.

However, fluoride has always had its critics. From researchers who cast doubt on whether it really impacts cavity protection to additional small-scale studies that also linked fluoride to potentially lower IQs, doubts to its efficacy exist.

The Canadian researchers who published this most recent study in the journal JAMA Pediatrics realize the public health implications of their work and hope this spawns further research. Noting the controversial nature of the findings given the number of pregnant women who are exposed to fluoridated water every day, the editor of JAMA Pediatrics, pediatrician and epidemiologist Dimitri Christakis of Seattle Children’s Hospital in Washington, added this editor’s note to its publication: 

“This decision to publish this article was not easy. Given the nature of the findings and their potential implications, we subjected it to additional scrutiny for its methods and the presentation of its findings….This study is neither the first, nor will it be the last, to test the association between prenatal fluoride exposure and cognitive development. We hope that purveyors and consumers of these findings are mindful of that as the implications of this study are debated in the public arena.”

Whether you’re pregnant right now or you know someone who is, the findings warrant a conversation with a healthcare provider to determine whether drinking fluoridated water should be avoided during pregnancy.


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The former Content Director at Parenting, parenting.com and several other brands, Ana Connery is a writer and content strategist whose work appears in USA Today, Reader's Digest, Real Simple, Cafe Mom/The Stir, Momtastic, and others.