If you are pregnant or hoping to become pregnant, you’re likely more aware of what’s going into your body on a regular basis. So a recent study on consuming fluoride during pregnancy that made headlines in August may have given you pause.
Led by researchers at York University in Toronto, the study followed pregnant women in six Canadian cities. In the studied sample, 41 percent lived in fluoridated communities and 60 percent lived in non-fluoridated communities. When they tested urine samples of the women in communities with fluoridated water, they found higher levels of fluoride. Then, when the children were ages three and four, it was found that the boys of the women with higher fluoride levels had lower IQ scores than children of the women with lower levels during pregnancy. There was no statistically significant association with IQ scores in girls based on maternal urine testing.
Fluoride is a natural mineral found in virtually all water bodies. It’s also usually added to toothpastes and mouthwashes and many regions add more fluoride to drinking water to ensure optimal levels for good oral health. Health Canada guidelines reference 1.5 mg/L as the maximum allowable amount of fluoride in drinking water. However, 0.7 mg/L is regarded as the most effective concentration for oral health benefits.
About 39 percent of Canadians live in communities with fluoridated water systems as of 2017, 74.4 percent of Americans did in 2014.
While fluoride is known to help prevent cavities and tooth decay, accumulating research has some medical experts concerned it may have negative consequences on fetus’ developing brains at certain concentrations. And the latest study is raising even more questions about its potential harm to fetuses—but it’s not without controversy.
Christine Till, a psychology professor at York University and one of the primary investigators in the study, says the study’s findings are a cause for concern. “This study indicates that fluoride ingestion during pregnancy at levels that are found in Canada may not be safe for unborn children. Ingesting too much from fluoridated water and other sources may be detrimental to brain development,” she says.
Till believes women should reduce their fluoride intake during pregnancy until more studies have been done to refute or confirm the findings.
But not everyone shares this belief. When the study hit the news in August, some called the study’s methodology into question, while others said the difference in IQ levels were not statistically significant when you considered the population as a whole (ie: both boys and girls).
Ferne Kraglund, a public health dentist and assistant dean at Dalhousie University’s Faculty of Dentistry in Halifax, stands by Health Canada’s guidelines.
“Pregnant mothers should not decrease their intake of fluoride. They need it to maintain their oral health, which is linked to the health of their newborn babies,” she explains.
Oral health is particularly important during pregnancy, as changing hormone levels can lead to pregnancy gingivitis, with gum swelling, bleeding and tenderness. If untreated, gingivitis may develop into advanced gum disease (periodontitis), affecting bone and gum tissue, which can lead to tooth loss. Some studies link preterm, low-birth-weight babies to severe periodontitis during pregnancy.
Others, however, say this latest study warrants some consideration. “We’ve known for years too much fluoride causes fluorosis [changes], but we didn’t think concentrations in water that are common in North America would be toxic to the developing nervous system, which the study shows it can be,” says Donald Cole, emeritus professor at the University of Toronto Dalla Lana School of Public Health and a physician in occupational environmental medicine.
He believes more studies are needed in young children to better understand the effects on IQ not only from exposure in utero, also the impact on babies and toddlers who drink the water.
For now, Cole says pregnant women should still feel comfortable using fluoridated toothpaste, as long as they don’t swallow it. To reduce fluoride intake, women can avoid black and green tea, which both contain the mineral. You could also consider purchasing specialized filtration systems that removes fluoride from tap water, if it’s in your budget. If you want to reduce fluoride intake, but are worried about tooth decay, you can reduce the amount of sugary and processed foods you eat, as they can cause tooth decay
However, Cole believes municipal fluoridated drinking water is still an important public health policy in places where women and their children are not provided free dental care, as this resource can reduce tooth decay among vulnerable children.
For its part, Health Canada is assessing the latest study. However, it believes the research to date indicates that the current maximum allowable 1.5 mg/L of fluoride in its guidelines poses no health concern, says Health Canada spokeswoman Marie-Pier Burelle.
William Fraser, an ob/gyn and researcher at the University of Sherbrooke in Quebec, is also giving advice cautiously. He says the new study is well designed and important, but he thinks more research is needed before drawing final conclusions about impact of fluoride in developing brains. The findings need to be replicated to strengthen the conclusions, he says.
“But in light of the current evidence, and until further research findings are available, mothers may wish to avoid fluoride supplementation during pregnancy,” he says. So far, he is not giving his patients any specific advice. “This is still fairly new. But over the next few months our medical group will consider having conversations on fluoride with women and what we will tell them. The study will generate a lot of discussion among practitioners and policy makers on if we should adjust fluoride levels and create policy around it,” he says.