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Question 729
Obstetric infection → Viral
Classification
Question
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Frequency of neonatal infection after late maternal chickenpox
Question Stem
A woman develops chickenpox 2 weeks before delivery. During counselling about neonatal risk, which estimate is most consistent with the guideline?
Options
A
Fewer than 1% of babies become infected and clinical disease is exceptional
B
Approximately 10% become infected and almost all are symptomatic
C
Approximately 25% become infected but none develop clinical varicella
D
Almost all babies become infected and approximately half develop clinical varicella
E
Up to 50% of babies may become infected and approximately 23% develop clinical varicella
Explanation
When maternal chickenpox occurs 1–4 weeks before delivery, up to 50% of babies may become infected and approximately 23% develop clinical varicella despite high titres of passively acquired maternal antibody. The timing of maternal infection relative to delivery is therefore important when counselling about neonatal risk.
Option Validity
A) the reported risk of neonatal infection is substantially higher.
B) these figures do not reflect those reported for maternal infection 1–4 weeks before delivery.
C) clinical neonatal varicella can occur.
D) infection is not described as occurring in almost all babies and clinical disease is not reported in approximately half.
Further Reading
RCOG Green-top Guideline No. 13, Chickenpox in Pregnancy, section 6.3.