US warns pregnant women of migraine drug risk

U.S. health regulators are warning doctors and women of child-bearing age that half-a-dozen medications used to treat migraine headaches can decrease children's intelligence if taken while their mothers are pregnant.

The Food and Drug Administration says the drugs, including Depakote and Depacon, should never be taken by pregnant women for the prevention of migraine headaches.

The pills, which contain valproate sodium, already carry a warning about the risk of birth defects. But the FDA said it is adding new warnings to the drugs' labeling after a study showed they decreased IQ scores in children whose mothers took them while pregnant.

Depakote and similar drugs are also used to treat bipolar disorder and seizures. The FDA said pregnant women should only take the drugs for those uses as a last resort.