For years there has been a debate about whether adding fluoride to drinking water was a plus (less tooth decay) versus those who felt there were possible health problems from the fluoride. Now the results of a Canadian study is raising serious concerns. The researchers followed 601 pregnant women from 6 cities in Canada, and found that pregnant women with higher levels of fluoride in their urine tended to have children with lower average IQs (which was measured at 3 or 4 years of age). As in the USA, some communities added fluoride to municipal drinking water, while others didn't.
The problem is that: "Fluoride crosses the placenta, 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." Not good. This is why studies are being done.
The researchers concluded the study with these words: "In this prospective birth cohort study from 6 cities in Canada, higher levels of fluoride exposure during pregnancy were associated with lower IQ scores in children measured at age 3 to 4 years. These findings were observed at fluoride levels typically found in white North American women. This indicates the possible need to reduce fluoride intake during pregnancy." [Note: in this study, the effect appeared to be stronger in boys than girls.]
Just note that this was an observational study (found an association, not a definite cause), but other studies also find such an association. (One study conducted in Mexico found that higher prenatal fluoride exposure was linked to lower IQs in 4 to 6 year old children.) Of course more studies are needed.
But in the meantime, one can try to lower fluoride exposure (in water) during pregnancy. One way is to drink less black tea (has high levels of fluoride) and green tea (varying levels of fluoride). Also, if fluoride is added to tap water, to try to drink less of that and perhaps more unfluoridated bottled water that is in glass bottles (because plastic leaches, and has more microplastics in it).
From The Scientist: Fluoride Exposure During Pregnancy Linked to Lower IQ In Sons
A study published yesterday (August 19) in JAMA Pediatrics reports an association between a pregnant mother’s urinary concentration of fluoride, often added to drinking water as a public health measure to reduce cavities, and the IQ of her son, but not her daughter, at age 3 or 4.
Fluoride prevents cavities by strengthening tooth enamel, and fluoridation of drinking water has been widely adopted in the US. Yet research has revealed potential risks associated with fluoride exposure during pregnancy. A small 2017 study conducted in Mexico, for example, has already suggested a link between prenatal fluoride exposure and IQ.
Using data collected as part of the Maternal-Infant Research on Environmental Chemicals program on pregnant mothers and their children born between 2008 and 2012 in six Canadian cities, the researchers examined the effects of mothers’ fluoride exposure during pregnancy and the IQ of their children at age 3 or 4. About 40 percent of expecting mothers in the study came from cities with fluoridated water. These pregnant mothers had average urinary fluoride levels of 0.69 milligrams per liter, compared with 0.4 milligrams per liter for women living in cities without fluoridated water. After controlling for potential confounding variables, the researchers found that a 1-milligram-per-liter increase in a mother’s urinary fluoride levels was associated with an approximately 4.5-point lower IQ score in her son.