April 15, 2009 / 9:05 PM / 10 years ago

IQ low in toddlers whose mothers took valproate

BOSTON (Reuters) - Children born to women who took the epilepsy drug valproate while pregnant had lower IQs at least up to age 3 than the children of women who took rival epilepsy drugs, researchers reported on Wednesday.

Babies rest on a bed inside a maternity ward in a file photo. REUTERS/Darren Whiteside

The findings add to evidence that the pill is harmful to unborn children. It is sold by Sanofi-Aventis as Epilim and as Depakine in the United States by Abbott Laboratories.

“This finding supports a recommendation that valproate not be used as a first-choice drug in women of childbearing potential,” Kimford Meador of Emory University in Atlanta and colleagues wrote in the New England Journal of Medicine.

Valproate does not just cause IQ problems. Evidence has been around for years that prenatal exposure can cause major congenital malformations in one in 10 children and British researchers found in December that it raised the risk of autism.

Yet it is still widely prescribed for epilepsy, migraines, bipolar disorder and other conditions, mostly by general practitioners who have not heard of its dangers, Meador said in a telephone interview.

“You have to wonder why so much of it is being written for women with epilepsy after all this time or, for that matter, for anything. I suspect it’s even worse for headache or bipolar, because that’s where most of the scripts are for this drug,” Meador said.

But for women who might become pregnant, simply halting the drug can be dangerous, causing more seizures, which can harm the fetus. And in roughly 5 percent of epilepsy patients, valproate, also known as valproic acid, is the only drug that works well.

“So I think the simple message is, try something else first,” said Meador.


About 25,000 children in the United States are born to mothers with epilepsy each year.

Meador and other members of the Neurodevelopmental Effects of Antiepileptic Drugs study found that IQ scores assessed at the three-year mark were typically six to nine points lower in children whose mothers had taken valproate, compared to cases where the women had used three other anti-epilepsy drugs.

Women who took GlaxoSmithKline Plc’s Lamictal, Novartis AG’s Tegretol and Pfizer Inc’s Dilantin, all had children who have roughly the same level of intelligence. All four drugs are available in generic form.

The lower the dose of valproate, the lower the risk that it will affect IQ, Meador said. There may not be a safe dose, but “if it’s the only drug that works, and it works in a low dose, then it may be OK,” Meador added.

“Most major congenital malformations can be detected with the use of prenatal screening, and many can be successfully treated surgically after birth, but cognitive impairment cannot,” Torbjorn Tomson of Karolinska Institute in Stockholm wrote in a commentary.

The researchers plan to follow the children for another three years.

Editing by Maggie Fox and Eric Beech

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