Anti-seizure drugs risky during pregnancy

NEW YORK (Reuters Health) - Treating seizures during pregnancy is a delicate balance. On the one hand, seizures are dangerous for mother and fetus. On the other, the medications used to treat seizure disorder - also known as epilepsy - may harm the fetus.

Now, new research suggests that it is largely the drugs used to treat seizures, and not the condition itself, that increase the risk of adverse pregnancy and birth outcomes.

Dr. Gyri Veiby, of Haukeland University Hospital, Bergen, Norway, and colleagues compared the outcomes of more than 2800 deliveries by women with epilepsy to those of more than 369,000 deliveries without epilepsy.

Of the women with epilepsy, about two-thirds (66%) did not use anti-seizure drugs during pregnancy. Those who did used medications such as valproate (marketed as Depakote) and phenobarbital, also used as a sedative in other conditions.

Infants born to mothers with and without epilepsy had very similar rates of major birth defects such as those involving the heart or lungs - about one in 40 births. However, those born to mothers who had taken valproate or multiple medications had a higher rate of birth defects, about six percent, particularly those involving the heart.

And those who had epilepsy but went untreated during pregnancy had a higher rate of birth defects involving the genitals, and of Down syndrome, a genetic condition that often involves mental retardation.

Finally, more women with epilepsy delivered by cesarean section. About 15 percent of women without epilepsy did so, while about 19 percent of those with medication-treated epilepsy during pregnancy and about 22 percent of those with untreated epilepsy during pregnancy.

The authors note that overall, many of the rates of complications and birth defects were lower than in previous studies, which may reflect the fact that doctors are switching to safer drugs, and that women are more likely to take folic acid during pregnancy, which has been shown to prevent many birth defects.

SOURCE: Epilepsia, September 2009.