Counselling · Intermediate · Infectious Diseases

Exposure to Chickenpox in Third Trimester of Pregnancy

Practise this PLAB 2 counselling station on Varicella Exposure in Pregnancy. 8-minute voice AI simulation with feedback on all 3 marking domains.

Clinical scenario

You are an FY2 doctor in the obstetric assessment unit. Mrs Deepa Rashid, a 31-year-old pregnant woman at 32 weeks gestation, has attended following exposure to chickenpox. Her nine-year-old daughter developed chickenpox rash four days ago. Deepa has never had chickenpox and is not sure of her immunity status. Please take a history of exposure, assess varicella immunity, counsel on risks to mother and fetus, discuss varicella-zoster immunoglobulin (VZIg), and provide safety netting.

Background notes: PMH: Generally healthy, no chronic illnesses, no serious infections

What this station tests

  • Determining immunity: varicella IgG antibody test, noting that 90% of UK adults are immune even without recalled history
  • VZIG within 10 days of exposure: does not prevent infection but attenuates severity in non-immune pregnant women
  • Third trimester risks: varicella pneumonia (maternal) and neonatal varicella (if delivery near maternal rash onset)
  • Aciclovir in pregnancy: safe when benefits outweigh risks if chickenpox develops
  • Distinguishing fetal varicella syndrome (first/second trimester) from neonatal varicella (around delivery)

How to use your 8 minutes

  • 0-1 min — Introduction: Introduce yourself, establish what patient already knows and understands.
  • 1-3 min — Explain Condition: Explain diagnosis or condition using chunk-and-check technique. Use simple language, avoid jargon.
  • 3-5 min — Management Options: Discuss treatment options. Shared decision-making. Risks, benefits, alternatives.
  • 5-7 min — Address Concerns: Explore and address specific concerns. Check understanding. Discuss lifestyle implications.
  • 7-8 min — Closing: Summarise agreed plan. Safety netting. Arrange follow-up. Written information offer.

Consultation approach

The opening

Chickenpox exposure in pregnancy is a clinical urgency because varicella can cause severe maternal illness and fetal complications. The candidate must determine immunity, assess exposure timing, and arrange prophylaxis if non-immune. Mrs Rashid is 31, 32 weeks pregnant, exposed to her stepdaughter's chickenpox. Open with: 'Mrs Rashid, I understand you have been in contact with chickenpox. Let me assess your risk and what we need to do.'

Core approach

Determine immunity. Has she had chickenpox before? She has not (or is uncertain). This means she may be non-immune. Check: has she had varicella vaccination? (Not routine in UK.) Previous blood test showing varicella IgG? Send urgent varicella IgG antibody test. Approximately 90% of UK adults are immune even if they do not recall having chickenpox.

Assess exposure. Her stepdaughter developed the rash 4 days ago. Chickenpox is infectious from 48 hours before rash onset until all lesions have crusted (typically 5 to 7 days). She lives in the same house, making this significant close contact. The exposure has already occurred.

Risks in pregnancy. Third trimester (32 weeks): varicella pneumonia is the main maternal risk (can be severe in adults, mortality 1 to 2% in pregnancy). Fetal risk at 32 weeks: neonatal varicella if delivery occurs within 7 days of maternal rash onset. Fetal varicella syndrome is a first/second trimester risk (not relevant at 32 weeks).

Management if non-immune. VZIG (varicella zoster immunoglobulin) should be given within 10 days of exposure (she is within the window at 4 days). This does not prevent infection but can attenuate severity.

Closing and safety netting

Urgent actions. Send varicella IgG today. If non-immune: arrange VZIG through the local virology or public health team. VZIG should be given as soon as possible (within 10 days of exposure). If IgG is positive (immune): reassure and no further action needed.

Advise: avoid further contact with the stepdaughter until lesions have crusted. Avoid contact with other pregnant women or immunocompromised individuals during the incubation period (10 to 21 days). Monitor for symptoms: if she develops a rash, contact the obstetric team immediately for aciclovir treatment (safe in pregnancy when benefits outweigh risks).

Safety net: 'If you develop a fever, rash, or any blistering lesions in the next 3 weeks, contact the maternity assessment unit immediately. Chickenpox in pregnancy can be serious but is very treatable if caught early.' Follow-up with IgG result.

How examiners mark this station

Examiners will assess your ability to explain varicella exposure in pregnancy and its management in a patient-centred way. Domain 2 (Clinical Management) and Domain 3 (Interpersonal Skills) are equally weighted and primary. Expect marks for accurate information delivery, shared decision-making, chunk-and-check technique, and addressing the patient's specific concerns. Domain 1 (Data Gathering) is assessed through how well you establish the patient's baseline understanding and elicit their concerns.

Domain 1: Data Gathering, Technical and Assessment Skills (Primary focus)

Scores well: Previous chickenpox history checked. Varicella IgG sent urgently. Exposure timing and significance assessed. Gestational age noted for risk stratification. Stepdaughter's infectious period calculated.

Costs marks: Not checking immunity. Not assessing exposure timing. Not noting gestational age.

Domain 2: Clinical Management Skills (Primary focus)

Scores well: VZIG arranged within 10-day window. IgG testing. Aciclovir for symptomatic disease mentioned. Contact avoidance advice. Obstetric team awareness. Symptom monitoring for 21 days.

Costs marks: Not arranging VZIG. Not testing IgG. Not mentioning aciclovir. No monitoring plan.

Domain 3: Interpersonal Skills (Throughout)

Scores well: Reassuring about the steps being taken. Explaining the risk proportionately (most adults are immune). Practical advice about the stepdaughter. Clear maternity assessment unit instruction.

Costs marks: Being alarmist. Not providing practical advice. Leaving her uncertain about what to do.

Common examiner feedback (and how to fix it)

Did not provide adequate explanation or plan to the patient

Fix: Use chunk-and-check: deliver one concept, check understanding, then move to the next. Offer all relevant treatment options with risks and benefits before helping the patient decide.

Did not sufficiently recognise or respond to the patient's feelings, concerns, or expectations

Fix: Before and during counselling, explicitly ask what concerns the patient most. Respond to emotional cues with empathic statements before continuing with information.

Common mistakes in this station

  1. Not checking varicella IgG. She may be immune despite no recalled history (90% of adults are). Candidates who assume she is non-immune without testing may give unnecessary VZIG, or candidates who assume she is immune without testing may miss a non-immune patient.
  2. Not arranging VZIG within the window. She was exposed 4 days ago and VZIG is effective within 10 days. Candidates who wait for IgG results before arranging VZIG may miss the window. If IgG returns positive, VZIG can be cancelled.
  3. Confusing fetal varicella syndrome with neonatal varicella. Fetal varicella syndrome (limb defects, eye abnormalities) is a first/second trimester risk. At 32 weeks, the concern is neonatal varicella if delivery is near maternal rash onset.

Resitting PLAB 2?

If counselling stations have been a challenge, the most common issue is information overload: delivering too much clinical detail without checking understanding. Practise the chunk-and-check technique until it becomes automatic. Remember that shared decision-making, not lecturing, is what scores highly in Domain 3.

Example opening

Hello, my name is Dr [Name]. I understand you've come in today to discuss [topic]. Before I explain things, could you tell me what you've been told so far, so I know where to start?

Frequently asked questions

How should I approach varicella exposure in pregnancy counselling in this PLAB 2 station?

Chickenpox exposure in pregnancy is a clinical urgency because varicella can cause severe maternal illness and fetal complications. The candidate must determine immunity, assess exposure timing, and arrange prophylaxis if non-immune.

What are examiners marking in this varicella exposure in pregnancy station?

Marks are won for: Previous chickenpox history checked. Varicella IgG sent urgently. Exposure timing and significance assessed. Gestational age noted for risk stratification. Marks are lost for: Not checking immunity. Not assessing exposure timing. Not noting gestational age.

What is the most common mistake candidates make in this varicella exposure in pregnancy station?

Not checking varicella IgG. She may be immune despite no recalled history (90% of adults are). Candidates who assume she is non-immune without testing may give unnecessary VZIG, or candidates who assume she is immune without testing may miss a non-immune patient.

How do I prepare for this station if I have not managed varicella exposure in pregnancy in clinical practice?

Structure beats experience here. Focus on vZIG within 10 days of exposure: does not prevent infection but attenuates severity in non-immune pregnant women. Work through the consultation approach above, then rehearse it aloud under the 8-minute time pressure so the structure holds up in the exam.

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