Prescribing for women with epilepsy is complicated by the potential teratogenicity of antiepileptic drugs. Current guidelines recommend that the most effective drug should be chosen before conception and prescribed at its lowest effective dose, ideally as monotherapy.¹² But which antiepileptic drug is safest in pregnancy?

Early research on the safety of antiepileptic drugs in pregnancy was unreliable. Several countries set up pregnancy registries in the late 1990s, and data from these registries are now appearing.

To date the UK Epilepsy and Pregnancy Registry has recruited more than 3500 women, of whom 72% were given antiepileptic monotherapy. The overall rate of major congenital malformation in women given antiepileptic drugs during pregnancy was 4.2%, compared with 3.5% in women with epilepsy who were not given such drugs.3 By three months of age, infants exposed to sodium valproate monotherapy during gestation had the highest frequency of major congenital malformation (6.2%), confirming similar findings from an Australian register.4 Lamotrigine monotherapy was associated with a 3.2% …