Planning for pregnancy in patients with epilepsy

Refer females with epilepsy who are planning conception to an expert.

For males with epilepsy who are planning conception, see Sodium valproate use in males of reproductive potential.

Babies born to mothers taking antiepileptic drugs have a 4 to 6% risk of major congenital malformations, which is about twice the risk for babies born to mothers without epilepsy.

All antiepileptic drugs may be teratogenic and none is the 'drug of choice’ in pregnancy (see teratogenic effects of antiepileptic drugs). The priority is to avoid seizures, which can seriously affect the patient and unborn child. The risks of antiepileptic drug therapy to the fetus, and the risks of suboptimally treated epilepsy to the mother and fetus, should be considered and discussed with the patient. When planning a pregnancy, make changes to the treatment regimen (eg attempting to withdraw antiepileptic drugs) well before conception. Most teratogenic effects occur before the pregnancy is confirmed, but neurodevelopmental effects probably depend on fetal drug exposure throughout the pregnancy.

Principles for treating epilepsy in females planning a pregnancy follow.

• Only continue treatment if needed to prevent seizures.
• Use monotherapy if possible.
• Minimise the dose of antiepileptic drug. In practice, the minimal effective dose can only be established by lowering the dose sufficiently to cause a seizure. If a dose is particularly high, it may be possible at least to reduce it. If the dose is reduced, driving is not permitted during the reduction and for 3 months after¹.
• Avoid sodium valproate unless other drugs are unlikely to prevent seizures (eg in patients with juvenile myoclonic epilepsy). If sodium valproate is essential, use 600 mg or less daily if possible.

Offer prenatal screening (alpha-fetoprotein measurement and ultrasound examination) to females taking antiepileptic drugs. Although unproven, folic acid may reduce the risk of neural tube defects in infants of females taking antiepileptic drugs. Use:

Vitamin K supplementation has been recommended to reduce the risk of haemorrhage in neonates whose mothers take enzyme-inducing antiepileptic drugs. However, there is no evidence to support its routine use.