Maternal disease, medication and substance effects on the fetus — formative SAQs

SAQ 1 — Valproate in pregnancy: counselling and prevention (20 marks, ~15 minutes)

A 26-year-old woman with juvenile myoclonic epilepsy, well controlled on sodium valproate, is found to be 8 weeks pregnant. She has been on valproate for 10 years and is frightened. She asks whether she should stop the medication immediately. ^[9]

Questions

1. Explain the principles of teratogenesis that determine the type of fetal harm from valproate, and why the timing of this presentation (8 weeks) is significant. (5 marks) ^[1]
2. Describe the specific risks and the named syndrome associated with fetal valproate exposure, including structural and neurodevelopmental effects. (5 marks) ^[11]
3. Outline your immediate counselling and management of this woman, including what you would and would not do with her medication. (5 marks) ^[9]
4. Describe the preventive measures that should ideally have been in place before conception, and what surveillance is now required for the remainder of the pregnancy. (5 marks) ^{[2] [9]}

Model answer (must-hit)

1. Teratogenic harm is timing-dependent: the first two weeks post-conception follow an all-or-none rule; weeks 3 to 8 (organogenesis) are the critical window for major structural defects; from week 9 onward the fetal period targets growth and neurodevelopment. At 8 weeks she is at the tail end of organogenesis — most structural risk has been incurred but neurodevelopmental risk continues. Valproate disrupts neural tube closure and histone deacetylase signalling, producing both structural defects and later neurodevelopmental harm. ^[1]
2. Fetal valproate spectrum disorder carries a major malformation rate around 6 to 10 percent — neural tube defects, cardiac anomalies and characteristic facies. Neurodevelopmental effects include reduced IQ, elevated autism risk and attentional difficulties, which may not be evident until early childhood. The 2019 European consensus statement codified the diagnosis. ^[11]
3. Do NOT stop valproate abruptly — uncontrolled seizures carry their own fetal and maternal risk. Refer urgently to neurology and perinatal medicine to individualise the risk-benefit balance and consider switching to lamotrigine or levetiracetam where the epilepsy phenotype allows. Counsel honestly about risk without adding anxiety about exposure that has already occurred. Confirm high-dose folic acid. ^[9]
4. Pre-conception, the ideal is a planned switch from valproate to the safest effective antiepileptic, high-dose folic acid 5 mg daily started before conception, reliable contraception until stable, and seizure optimisation. Antenatal surveillance now requires a detailed fetal anatomy ultrasound at 18 to 20 weeks and a fetal echocardiogram, with planned developmental follow-up of the child. ^{[2] [9]}