Varicella Zoster Infection in Pregnancy

Question 1

Definition

Answer 1

Chickenpox is caused by the varicella zoster virus (VZV)

Question 2

Why is VZV dangerous in pregnancy

Answer 2

• More severe cases in the mother, such as varicella pneumonitis, hepatitis or encephalitis
• Fetal varicella syndrome
• Severe neonatal varicella infection (if the mother develops rash between 5 days before and 2 days after birth there is a risk of neonatal varicella, fatal in around 20% of cases)

Question 3

Immunity and Exposure

Answer 3

Mothers that have previously had chickenpox are immune and safe.
- When in doubt IgG levels of VZV
- Non immune women offered vaccine before or after pregnancy
Prophylaxis during pregnancy = Oral aciclovir (or valaciclovir) is now the first choice of PEP for pregnant women at any stage of pregnancy
antivirals should be given at day 7 to day 14 after exposure, not immediately. (Used to be VZIG but due to shortage guidelines changed)

Question 4

Treatment

Answer 4

Oral aciclovir should be given if the pregnant women is ≥ 20 weeks and she presents within 24 hours of onset of the rash
if the woman is < 20 weeks the aciclovir should be ‘considered with caution’

Question 5

Foetal varicella syndrome

Answer 5

1% of cases of chickenpox in pregnancy
Occurs in the first 20 weeks of gestation.
Studies have shown a very small number of cases occurring between 20-28 weeks gestation and none following 28 weeks.

Signs and symptoms:
- Fetal growth restriction
- Microcephaly, hydrocephalus, and learning disability
- Scars and significant skin changes located in specific dermatomes
- Limb hypoplasia (underdeveloped limbs)
- Cataracts and inflammation in the eye (chorioretinitis)