Drinking Tap Water During Pregnancy Could Harm Your Kid Later In Life, Study Says

Ever since 1945, the chemical fluoride has been added to most public water supplies to help reduce the advent of cavities. In fact, a full two-thirds of the public water supply in the United States has fluoride added to it. A fact that has been hotly debated for decades — and apparently with good reason. A new study found that drinking tap water during pregnancy can harm children later on in life, and the debate over water fluoridation has been brought to the floor once again.

The study, which was published on Tuesday in the Environmental Health Perspectives journal, looked at 300 sets of mothers and their babies living in Mexico over a period of 12 years. While fluoride is not actually added to the water in Mexico as it is in the United States, it is a natural occurrence in the water there and can be found in salt, milk, and toothpaste.

The researchers tested fluoride levels in the mothers' urine samples, and what they found was interesting. When higher levels of fluoride were found in a mother's urine sample while the child was in utero, they tended to have lower IQs. The test scores in the children involved in the study began to drop when fluoride levels were higher than 0.8 milligrams per one liter of urine.

While the researchers found that fluoride in prenatal urine samples could be linked to a drop in IQ (notably beginning at age 4, and then again at 6 and 12) they also found that fluoride levels in a child's urine did not seem to affect their intelligence, according to CNN.

Researchers tested for the chemical compound in the test children's urine samples between the ages of 6 and 12. As study lead author and dean of the Dalla Lana School of Public Health at the University of Toronto told CNN:

Childhood exposure to fluoride is safer than prenatal. There is pretty good science now to support the fact that the fetal system tends to be more sensitive to environmental toxicants than once the child is born.

So how does the information gathered in this study translate to pregnant women living in the United States? After all, the women of Mexico were ingesting naturally occurring fluoride rather than supplemental fluoride added to their water supply to combat cavities (and it is important to note that dental hygiene, including cavity prevention, is especially important during pregnancy). Dr. Howard Hu, who studies environmental health at the University of Toronto, told Newsweek that the levels of fluoride found in the mothers of Mexico are not significantly different from those in the United States, where around 75 percent of the population has fluoride in their public water systems:

If you just assume for the moment that fluoride in the urine of pregnant women is the same as it is in nonpregnant women, then these levels are a bit higher — but not hugely higher — than that seen in general population samples in North America.

This was not the first time a connection has been reported between fluoride consumption and neurodevelopment. Linda Birnbaum, the director of the National Institute of Environmental Health Sciences, told CNN:

There have been similar findings related to exposure to fluoride and IQ from children in China. So this observation or association has been reported before.

Those who oppose fluoride in drinking water will undoubtedly point to this recent study linking fluoride as a potential neurotoxin as another reason to end artificial fluoridation. The argument has long been made that, since the beginning of the practice over 60 years ago, people are now receiving fluoride from more sources than just water, according to

If you are concerned about drinking tap water while pregnant, it's a good idea to consult your doctor about the possible side effects.

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