Lower IQ in children is strongly associated with higher levels of maternal fluoride exposure during pregnancy.
Association between maternal fluoride exposure during pregnancy and IQ scores in offspring in Canada
In this Canadian study, maternal exposure to higher levels of fluoride during pregnancy was strongly associated with lower IQ in children. In addition, the study found that women living in areas with fluoridated tap water had significantly higher average concentrations of fluoride in their urine compared to women without fluoridated tap water. Fluoridated cities in Canada use the same fluoride concentration (0.7 milligrams per liter) as the U.S. has used since 2015—a concentration recommended by the CDC as “optimal.” The authors raise concerns about the safety of maternal exposure to “optimally fluoridated water” and note that, at the population level, their results translate to “millions of IQ levels lost.”