Maternal disease, medication and substance effects on the fetus — structured clinical encounter

Station brief (candidate)

You are the general paediatric registrar in a pre-conception counselling clinic. Priya is 24 and has juvenile myoclonic epilepsy, well controlled on sodium valproate for 8 years. She and her partner want to start a family. She has read online that valproate harms babies and arrives anxious, considering stopping her medication. You have 12 minutes with the family and 5 minutes for examiner discussion. [9]

Information available on request

• Juvenile myoclonic epilepsy diagnosed at age 16, seizure-free for 3 years on valproate monotherapy. [9]
• No other medications, no recreational substances, does not smoke, occasional alcohol now stopped. [9]
• Body mass index normal, no other medical history, partner well. [9]
• Family history unremarkable. [9]

Tasks

1. Explain to Priya the principles of how medications can affect the fetus, framed around the timing of exposure, without frightening her. [1]
2. Describe the specific risks and the named syndrome associated with fetal valproate exposure. [11]
3. Outline the pre-conception plan: medication review and switching, folic acid, contraception and surveillance. [2] [9]
4. Address her anxiety about her current medication and explain why stopping it abruptly is not the right step without a plan. [9]

Marking anchors

Must-hit

• Explains timing-dependent teratogenesis accurately and accessibly. [1]
• Names fetal valproate spectrum disorder and its structural and neurodevelopmental risks. [11]
• Describes the safer alternatives (lamotrigine, levetiracetam) and the need for a planned, supervised switch with neurology before conception, not abruptly in pregnancy. [9] [12]
• Prescribes high-dose folic acid 5 mg daily starting now. [2]
• Uses reliable contraception until the safest regimen is established. [9]

Merit

• Discusses lamotrigine pharmacokinetics in pregnancy (clearance rises, levels fall, requires monitoring and dose adjustment) as a marker of deeper understanding. [9]
• Plans detailed fetal anatomy ultrasound at 18 to 20 weeks and a fetal echocardiogram. [11]
• Addresses the psychosocial and communication dimensions: honest risk, supportive tone, anxiety reduction, shared decision-making. [9]

Fail

• Advises stopping valproate immediately and "trying to conceive naturally". [9]
• Dismisses the teratogenic risk of valproate. [11]
• Fails to mention folic acid. [2]
• Uses a stigmatising or frightening tone that would drive the patient away from care. [9]

Examiner discussion prompts

• "How would you adjust the plan if Priya were on valproate and lamotrigine together?" — expects a discussion of polytherapy risk and the aim of monotherapy on the safest agent. [10]
• "What developmental surveillance would the child need after birth?" — expects planned developmental follow-up given valproate's neurodevelopmental signature. [11] [12]
• "If Priya became pregnant tomorrow before any switch, what would you do?" — expects referral to neurology and perinatal medicine, no abrupt cessation, confirmation of folate, and targeted antenatal surveillance. [9]