Epilepsy in pregnancy

Question 1

What is the main principle of epilepsy management in pregnancy?

Answer 1

While the risks to pregnancy from seizures outweigh those from anticonvulsant medication…

…seizures should still be controlled with the minimum possible dose of the optimal drug

Question 2

What is the effect of pregnancy on epilepsy?

Answer 2

No consistent effect - although some women have an increased incidence of fits, some a decrease and some no difference

Question 3

Why might seizures increase in frequency in pregnancy?

Answer 3

• Altered drug metabolism may cause low serum levels of AEDs
• Sleep deprivation
• Stress
• Poor compliance with medication

NB: if seizures increase then this should prompt increasing dose of AEDs esp if drug levels are subtherapeutic

Question 4

What is the mortality rate associated with epilepsy in pregnancy?

Answer 4

x10 increase in mortality among pregnant women with epilepsy compared to non-epileptic pregnant women

1 in 20 indirect maternal deaths occur in women with epilepsy

Question 5

What is the fold increase in risk of fetal abnormality associated with taking AEDs? Why is monotherapy recommended?

Answer 5

All AEDs are associated with a 2–3-fold increased risk of fetal abnormality (5–6%) compared with unexposed epileptic mothers where risk is 1-2%

Polytherapy increases the risk of major congenital abnormality by about 3% for each additional AED.

Question 6

What fetal abnormalities are associated with AEDs?

Answer 6

Major fetal abnormalities:*

• Neural tube defects
• Facial clefts
• Cardiac defects

In addition each drug is associated with a specific syndrome which includes developmental delay, nail hypoplasia, growth restriction and midface abnormalities (with valproate this is dose dependent occurring at >1000mg/day so this should be avoided)

*Associated with AEDs including sodium valproate, carbamazepine, phenytoin, phenobarbitone

Question 7

Can fetal abnormalities be detected antenatally in AED use?

Answer 7

Yes - many can be detected by USS so a detailed anomaly scan should be offered to all women

Question 8

What can occur during a seizure leading to fetal compromise?

Answer 8

Hypoxia - both fetal and maternal

Question 9

What should be done in epilepsy in a woman trying to conceive?

Answer 9

1. Reduce medications to monotherapy if possible i.e. preferred AED is lamotrigine
2. High dose folic acid 5mg OD - pre-conception to 12 weeks’

Sodium valproate is contraindicated due to risk of neural tube defects

Question 10

What is the management of epilepsy antenatally?

Answer 10

• Review in joint epilepsy and obstetric clinic
• Serial growth scans 4-weekly at 28, 32 and 36 weeks

NB: no need to monitor AED levels routinely. If seziure-free for 2 years then considder discontinuing medication.

Additional counselling:

• Stress importance of compliance with medication
• Explain risk of congenital malformation.
• Explain risk from recurrent seizures.

Question 11

Levels of which AED may need to be increased during pregnancy?

Answer 11

Lamotrigine - levels fall rapidly during pregnancy which may increase seizure activity

Question 12

What is the intrapartum management in pregnancy with epilepsy?

Answer 12

Continue medication as normal during labour

Question 13

What is the management of epilepsy postnatally?

Answer 13

• Encourage breastfeeding - although avoid for a few hours after taking medication
• Provide information on safe handling of neonate e.g. stay close to the ground, change the baby on the floor
• Restart contraception

Question 14

Apart from epilepsy, what are the other causes of seizures in pregnancy?

Answer 14

• Epilepsy
• Eclampsia
• Encephalitis or meningitis
• SOL (e.g. tumour, tuberculoma)
• CVA
• Cerebral malaria or toxoplasmosis
• Thrombotic thrombocytopaenic purpura
• Drug and alcohol withdrawal
• Toxic overdose
• Metabolic abnormalities (e.g. hypoglycaemia)