JAMA Pediatrics released a study Monday August 19th revealing mothers who were exposed higher amounts of fluoride and fluoridated water had children with lower IQ scores.

Researches studied 512 pregnant women from six Canadian cities and measured their exposure to fluoride. When their children reached the ages of 3 or 4 the children were given an IQ test. Women who had been exposed to higher levels of fluoride were shown to have lower IQ scores.

The study determined a 1 mg per liter increase in fluoride concentration exposure resulted in a 3.7 point IQ decrease among both boys and girls. Though higher concentrations seem to affect boys more so than girls. Boys with mothers who had higher exposures had 3 IQ point lower scores than boys with mothers least exposed.