Chickenpox exposure in pregnancy

Question 1

What are chickenpox and shingles?

Answer 1

Chickenpox is caused by primary infection with varicella-zoster virus.

Shingles is caused by the reactivation of dormant virus in dorsal root ganglion.

Question 2

What are the risks of chickenpox exposure to the mother?

Answer 2

5 times higher risk of pneumonitis

Question 3

How common is fetal varicella syndrome and what are its features?

Answer 3

1% before 20 weeks of gestation, few cases between 20-28 weeks, none >28 weeks

Features: skin scarring, eye defects (microphthalmia), limb hypoplasia, microcephaly and learning disabilities

Question 4

What are other serious risks to the fetus?

Answer 4

Shingles in infancy: 1-2% if exposure in second/third trimester
Severe neonatal varicella: if the mother develops rash between 5 days before and 2 days after birth there is a risk of neonatal varicella, which may be fatal to the newborn child in around 20% of cases

Question 5

How is chickenpox exposure in pregnancy managed?

Answer 5

1. If doubt about whether mother has it, maternal blood should be checked for varicella antibodies
2. Previously, varicella zoster immunoglobulin (VZIG) used for treatment.
3. Now, oral aciclovir 7-14 days after exposure given

Question 6

How is chickenpox in pregnancy managed?

Answer 6

1. Seek specialist advice
2. Oral aciclovir should be given if the pregnant women is ≥ 20 weeks and she presents within 24 hours of onset of the rash
3. At <20 weeks, consider aciclovir with caution