A new study is raising questions about one of the top public health inventions of the 20th century.
Fluoride has long been hailed as a key ingredient to better dental health.
Now, data published in the journal JAMA Pediatrics suggests it may have negative consequences.
In a study of more than 500 women, researchers in Canada found those who drank fluoridated water while pregnant had children with lower IQ scores.
The study's authors say more research is needed to explore the connection between fluoride consumption and a decrease in children's intelligence.
In the meantime, health experts recommend women reduce their fluoride intake during pregnancy.