Epilepsy, Contraception, Pregnancy and Breastfeeding

Women with epilepsy should ideally plan their pregnancies to optimize their epilepsy treatment well in advance of conception. This process therefore starts already with a discussion of methods for birth control. It has been known for decades that enzyme inducing antiepileptic drugs (AEDs) can reduce serum concentrations of oral contraceptives and thus lead to an increased risk of failure. Combined oral contraceptives, on the other hand, can induce the metabolism of lamotrigine leading to a reduction of lamotrigine levels by approximately 50%. Intrauterine contraceptive devices is one method to avoid these pharmacokinetic interactions. Major changes in AED treatment should ideally be completed and assessed well in advance of conception. During pregnancy, the potential teratogenic effects of AEDs need to be balanced against fetal and maternal risks associated with uncontrolled seizures. The goal is to maintain control of in particular major convulsive seizures with minimal exposure the fetus to potentially teratogenic drugs. AEDs differ in their teratogenic potential, with valproate associated with greater risks for major congenital malformations and adverse effects on the child’s cognitive and behavioral development. Valproate should therefore, whenever possible, be avoided in pregnancy, and regulatory bodies, such as EMA, have issued restrictions on its use in women of childbearing age. Topiramate has been associated with impaired intrauterine growth, and there are signals of increased risk for malformations with this drug. In general, teratogenic risks appear to be dose-dependent and the aim should be to established the lowest effective dose before pregnancy, regardless of which AED that is used. Many AEDs undergo pronounced changes in their pharmacokinetics during pregnancy, resulting in significant decline in the serum concentration with associated risk of deterioration in seizure control. This is particularly pronounced for lamotrigine, but seen also with oxcarbazepine and levetiracetam. Drug level monitoring is therefore often recommended during pregnancy. The value of this is increased if the optimal serum concentration has been documented before pregnancy to serve as an individual reference and target concentration. Data are consistent when it comes to the benefits of breastfeeding. Although some AEDs can appear in significant serum concentrations in the infant, breastfeeding can in general be encouraged even if the woman is under treatment with AEDs.