Epilepsy in pregnancy — structured SAQ (15 marks)

(a) Preconception counselling and management (5 marks)

One mark per point, maximum five. [3][4]

• Preconception folic acid 5 mg daily at least three months before conception, continued through at least the first trimester.[4]
• Continue lamotrigine at the current dose. Lamotrigine is one of the preferred AEDs in pregnancy (EURAP 2018 malformation rate 2.9 percent, within the unexposed range).[1]
• Plan dose monitoring: lamotrigine clearance rises 50 to 100 percent in pregnancy because of oestrogen-induced UGT1A4 glucuronidation. Check serum level every trimester and increase the dose empirically as clearance rises.[4][5]
• Detailed anatomy scan at 18 to 20 weeks with attention to cardiac and neural tube structures.[3]
• MDT with neurology and anaesthetics; counsel on the trade-off: never stop AEDs abruptly because the harm of uncontrolled seizures exceeds the marginal benefit of stopping.[3]

(b) Breakthrough seizures at 24 weeks (4 marks)

One mark per point, maximum four. [4][5]

• Assessment: airway, oxygen, glucose, blood pressure and urinalysis (exclude eclampsia after 20 weeks), neurological examination, drug level (lamotrigine), fetal cardiotocography if viable.[3]
• Pharmacological adjustment: check serum lamotrigine level — it will typically have fallen because clearance has risen. Increase the lamotrigine dose empirically (often doubling by the third trimester) and titrate to seizure control and serum level.[4][5]
• Identify the precipitant: non-adherence, sleep deprivation, hyperemesis with reduced absorption, infection. Treat the precipitant.[3]
• Plan rapid postpartum dose reduction: lamotrigine clearance falls rapidly after delivery; reduce the dose to the pre-pregnancy baseline over 1 to 2 weeks to avoid toxicity.[4][5]

(c) EURAP registry comparative malformation rates (4 marks)

One mark per drug with rate, maximum four. [1]

From the Tomson Lancet Neurology 2018 EURAP comparative study (n=7355 monotherapy exposures):

• Valproate: 10.3 percent (142 of 1381) — the outlier, dose-dependent (under 700 mg per day 5.9 percent; at or above 1500 mg per day 24 percent).[1][2]
• Carbamazepine: 5.5 percent (107 of 1957) — dose-dependent.[1]
• Lamotrigine: 2.9 percent (74 of 2514) — within the unexposed range.[1]
• Levetiracetam: 2.8 percent (17 of 599) — within the unexposed range.[1]

(d) Intrapartum and postpartum (2 marks)

One mark per point, maximum two. [4][6]

• Continue lamotrigine through labour; avoid pethidine (norpethidine lowers seizure threshold); regional anaesthesia preferred; seizure precautions; neonatal vitamin K 1 mg intramuscular at birth.[3][4]
• Postpartum: reduce lamotrigine to pre-pregnancy dose over 1 to 2 weeks; encourage breastfeeding (Meador NEAD 2014 showed no cognitive harm and a 4-point IQ advantage at age 6 in breastfed children of mothers on AEDs); address sleep deprivation and seizure triggers; contraception review (enzyme-inducing AEDs reduce combined oral contraceptive efficacy — lamotrigine is an exception but levels may be affected).[4][6]