New research found that fluoride exposure via drinking water may increase the risk of hypothyroidism in pregnant women. In a smaller subset of participants, the researchers found lower IQ scores between boys whose mothers had been diagnosed with hypothyroidism compared to boys whose mothers had normal thyroid levels. Earlier research found an association between maternal fluoride exposure in pregnancy and lower IQ in boys, and this new research may explain these earlier findings, according to Ph.D. student Meaghan Hall. In the study, a half-milligram-per liter increase in drinking-water fluoride levels, which may not sound like much, but is roughly the...