A recent study suggests that children exposed to the epilepsy drug valproate in the womb are more likely to have a low IQ score than children exposed to other anti-seizure medications.
“This drug should not be used as a first choice in women of childbearing age,” says lead author Dr. Kimford Meador of the University of Florida in Gainesville. If valproate is used, dosages should be kept as low as possible. And for women with epilepsy who are planning a pregnancy, drug decisions should ideally be made prior to becoming pregnant.
Meador says it is important to remember that the majority of children born to women on valproate are normal, and a pregnant woman who reduces or stops her medication without consulting her doctor risks seizures that could seriously injure her or her fetus.
However, he adds that many family doctors may not be aware of the risks of taking valproate during pregnancy. “The reason I would conclude that is sales of valproate last year rose 28 per cent,” he says. “This drug is not just used for seizures for epilepsy. In fact, over half the prescriptions were written for other indications, such as bipolar disease and migraines.”
Meador and his colleagues tested the IQs of 185 two-year-olds whose mothers were on single-drug treatment of epilepsy during pregnancy. The medications included lamotrigine, carbamazepine, phenytoin and valproate.
After the researchers accounted for factors such as the mother’s IQ and alcohol use, they found that more valproate-exposed children had IQs in the range of mental retardation compared with those exposed to the other drugs (24 per cent versus 13 per cent of carbamazepine-exposed children, 12 per cent of phenytoin-exposed children and 11 per cent of lamotrigine-exposed children).
The team is planning to study these children until they are six years old.