Antiepileptic drugs in pregnancy
Women who suffer from epilepsy should plan their pregnancies. There is an association between epilepsy, antiepileptic drugs and major congenital abnormalities but seizures during pregnancy carry considerable risks so expert medical advice is required. It is preferable for an epileptic woman to be on medication that controls her fits than to risk seizures by coming off treatment so selection of the least teratogenic drug is important.
All antiepileptic drugs are linked to birth defects but carbamazapine (tegretol) has the lowest risk, compared with valproic acid (depakin) or phenytoin (epanutin) so it should be considered the medication of choice in pregnancy. The latest data from Jentink et al (BMJ 2010;341:c6581) are drawn from the EUROCAT Antiepileptic Study Database and show that carbamazapine was associated with a raised incidence of spina bifida but the absolute risk was small – 2 per 1000 against a background rate at 1 per 1000. Other antiepileptic drugs, as single or combination therapy had higher risk ratios.
It is advised that at-risk women stabilise their maintenance therapy on carbamazapine (tegretol) before conceiving and remain on it throughout pregnancy. Additional folate is also advised as well as checking for neural-tube defects in the first trimester