Epilepsy in Pregnancy

Epilepsy in pregnancy is recurrent seizures in a woman who is pregnant or planning pregnancy. Seizures harm the mother and fetus, while some antiepileptic drugs (especially valproate) cause malformations and lower child intelligence. Most women have a normal pregnancy if the drug is chosen and dosed carefully.

• Seizure frequency is unchanged in most women.
• Risk factors for worse control: missed doses, sleep loss, vomiting, falling drug levels.
• Never stop an effective drug on learning of pregnancy.

Women have known epilepsy with generalised tonic clonic, focal or absence seizures, and any first seizure needs exclusion of eclampsia, meningitis, cerebral malaria, venous sinus thrombosis and hypoglycaemia. Record seizure type, frequency and drug history.

• Seizure with blood pressure above 140/90 mmHg and proteinuria is eclampsia until proven otherwise.
• Postictal confusion lasts minutes to hours.
• Differential diagnosis: eclampsia, syncope, cardiac arrhythmia, functional seizure, cerebral malaria, meningitis, cerebral venous thrombosis, hypoglycaemia, alcohol withdrawal.
• Complications: injury, status epilepticus, miscarriage, fetal hypoxia, preterm birth, neural tube defect and other malformations, haemorrhagic disease of the newborn from vitamin K deficiency, sudden unexpected death in epilepsy.

The approach is clinical with tests to exclude other causes of seizure.

• Blood pressure, urine protein, glucose, electrolytes, calcium, magnesium, full blood count, malaria test.
• Drug levels (phenytoin, carbamazepine, lamotrigine) before pregnancy, at each trimester and if seizures occur.
• EEG and MRI without gadolinium for new onset epilepsy; lumbar puncture if meningitis is suspected.
• Detailed anomaly scan at 18 to 20 weeks, including spine and heart.

The principle is the lowest effective dose of one safe drug, folic acid and planned delivery.

• Supportive: adherence; regular sleep; avoid alcohol; safety advice (no baths alone, car safety); breastfeeding is encouraged; change and bathe the baby on the floor or a low surface.
• Pharmacological: folic acid 5 mg oral daily from before conception to 12 weeks; lamotrigine 100 to 400 mg oral daily in 2 divided doses (increase by 25 to 50 percent with monitoring of levels, and reduce after delivery); levetiracetam 500 mg to 1.5 g oral 12-hourly (maximum 3 g daily); carbamazepine 200 to 600 mg oral 12-hourly (maximum 1.2 g daily) with modified release tablets; phenytoin 300 mg oral daily and phenobarbital 60 to 180 mg oral at night only if safer drugs are unavailable; avoid sodium valproate; vitamin K 1 mg IM to every newborn; acute seizure: diazepam 10 mg IV over 2 minutes (or lorazepam 4 mg IV), repeat once after 10 minutes; status epilepticus: phenytoin 20 mg/kg IV at no more than 50 mg per minute, or levetiracetam 60 mg/kg IV (maximum 4.5 g) over 15 minutes; for eclampsia give magnesium sulphate 4 g IV over 20 minutes then 1 g per hour for 24 hours.
• Procedures: none; caesarean section only for obstetric reasons or uncontrolled seizures in labour.
• Special groups: enzyme inducing drugs (carbamazepine, phenytoin, phenobarbital) lower hormonal contraception effect, so use depot medroxyprogesterone 150 mg IM every 13 weeks or a copper intrauterine device; neonates of women on phenobarbital or benzodiazepines are monitored for withdrawal and sedation.
• Red flags: seizure lasting above 5 minutes, repeated seizures, seizure with headache and hypertension, confusion, fever with seizure, missed drug doses.
• Follow-up: review every 4 weeks; drug levels each trimester and at 4 weeks postpartum; anomaly scan at 18 to 20 weeks; reduce lamotrigine to pre-pregnancy dose in the first 3 weeks after delivery.