30th June 2023

Epilepsy

Epilepsy is a relatively common condition in women of childbearing age, with idiopathic epilepsy being the leading underlying cause. Women with well-controlled epilepsy pre-pregnancy can be reassured that, providing they continue to take their medication and the therapeutic levels of these are maintained, the pregnancy is likely to be straightforward.

SUDEP (Sudden Unexpected Death in Epilepsy) is one of the leading causes of indirect maternal death in the UK, possibly linked to the changes with drug levels and fatigue. Labour and the immediate postpartum period are the most common times for seizures.

Most epileptic seizures will not have a significant impact on the growing fetus; status epilepticus is understandably more dangerous for both mother and baby.

Anti-epileptic drugs

Due to the well-published risks of some anti-epileptic drugs, women are often concerned about continuing their medication during pregnancy. This concern can then be exacerbated by vomiting in early pregnancy leading to drug levels which are not therapeutic. Later in pregnancy, increased drug clearance and larger volumes of distribution also lead to sub-therapeutic levels, along with lower gastric absorption in labour itself.

Sodium valproate is linked to neurodevelopmental delay and neural tube defects and so should only be used by women and girls who are on the pregnancy prevention program with regular reviews and discussion about the avoidance of pregnancies.

Newer agents such as lamotrigine and levetiracetam appear to have the lowest risk of congenital abnormalities, with phenytoin and carbamazepine also at a lower level than valproate. High dose folic acid (5mg daily) seems to reduce the risk of teratogenicity, as does using a minimal dose that stabilises seizure activity and avoidance, if possible, of polytherapy.