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Lamotrigine Monitoring in Pregnancy — SCE Neurology MCQ

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ModerateEpilepsy & Seizure DisordersLamotrigine Monitoring in PregnancySCE Neurology

A 45-year-old woman with known epilepsy has a seizure during pregnancy at 34 weeks. She is on lamotrigine. Her lamotrigine level is well below her pre-pregnancy baseline despite dose increases. She is adherent to her medication. What is the recommended monitoring approach for lamotrigine levels during pregnancy?

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Correct answer: B — Monthly lamotrigine level monitoring with dose adjustment to maintain the pre-pregnancy target level

Lamotrigine clearance increases dramatically during pregnancy (up to 300% by the third trimester) due to oestrogen-induced glucuronidation. NICE NG217 and ABN guidelines recommend establishing a pre-pregnancy baseline lamotrigine level, then monitoring monthly (or more frequently) during pregnancy, with dose adjustments to maintain the baseline level. After delivery, the dose must be reduced promptly (within 2–3 weeks) as clearance returns to normal rapidly, risking toxicity. A: Levels change substantially. C: Waiting for seizures is too late. D: Trimester-only monitoring is insufficient. E: Lamotrigine is one of the safest AEDs in pregnancy.

Reference: NICE NG217 (2025); ABN Epilepsy and Pregnancy Guidelines