EMQ — Extended Matching Question · Review
Question 769
Obstetric infection → Viral
Classification
Question
EEMQQuestion Header
Select the single most appropriate interpretation of the evidence.
Question Stem
A pregnant woman asks whether VZIG has been proven to prevent fetal varicella syndrome if she subsequently develops chickenpox. Which statement best reflects the evidence reviewed in the guideline?
Answer Bank
A
Randomised trials prove that VZIG completely prevents FVS
B
Observational data suggest VZIG may reduce FVS, but the evidence is subject to reporting bias
C
VZIG increases the incidence of FVS
D
VZIG has no reported association with fetal outcome
E
VZIG is therapeutic once the maternal rash develops
F
VZIG eliminates the need for fetal surveillance after maternal infection
G
VZIG guarantees that maternal chickenpox will not develop
H
The evidence establishes a precise 0% residual fetal risk
Correct Answer
B. Observational data suggest VZIG may reduce FVS, but the evidence is subject to reporting bias
Explanation
A meta-analysis of observational case series reported no FVS among 142 babies whose mothers developed varicella despite receiving VZIG compared with 14 of 498 (2.8%) without VZIG. However, other cases have occurred after VZIG and the guideline emphasises that the evidence is observational and may be affected by reporting bias. It therefore supports a possible reduction in risk rather than proof of complete prevention.
Option Validity
A) The evidence is observational rather than randomised and does not establish complete prevention.
C) The evidence suggests possible reduction rather than increased risk.
D) Observational fetal-outcome data are described.
E) VZIG has no therapeutic benefit once chickenpox has developed.
F) Maternal infection still requires appropriate fetal counselling and surveillance.
G) Chickenpox may still develop despite PEP.
H) A zero residual risk cannot be concluded from these data.
Further Reading
RCOG Green-top Guideline No. 13. Chickenpox in Pregnancy. Royal College of Obstetricians and Gynaecologists; January 2015, minor update 2024.