Epilepsy drug link to spina bifida

Women with epilepsy who take the commonly used anti-epileptic drug (AED), carbamazepine, may have an increased risk of having a child with spina bifida, the results of a new study indicate.

Spina bifida is the name given to a birth defect in which the spinal column fails to form properly while the baby is developing in the womb. It is one of the most common of a group of birth defects known as neural tube defects.

Dutch researchers carried out a review of all published studies to identify specific major malformations linked with carbamazepine use in the first three months of pregnancy.

Carbamazepine is one of the most commonly used AEDs in Europe among women of reproductive age.

The researchers found that spina bifida was the only specific major congenital malformation significantly associated with exposure to carbamazepine use. In fact, the condition was 2.6 times more likely in the infants of women who had taken carbamazepine compared with no AED.

The researchers stressed that ‘although most anti-epileptic drugs taken during pregnancy significantly increase the risk for one or more specific congenital malformations, the occurrence of these malformations is nevertheless rare...most exposed pregnancies result in a baby without malformation'.

Their findings were published in the British Medical Journal.

However, they added that the risk of spina bifida appeared to be even greater when another AED, valproic acid, was used. A study by the team, which was published in the New England Journal of Medicine earlier this year, found that women on valproic acid were six times more likely to have a baby with spina bifida and seven times more likely to have an outcome with hypospadias (a condition where a boy's urinary opening develops in the wrong part of the penis or in the scrotum), compared with women using other AEDs.

The team concluded that although the overall risk of birth defects is low for women taking AEDs, ‘the best option regarding anti-epileptic drug treatment can be chosen only on an individual basis by the woman and neurologist before pregnancy, weighing the benefits of epilepsy control against the risk of teratogenicity (foetal defects).'

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[Posted: Fri 03/12/2010]