Chickenpox / Shingles Exposure in Pregnant Women

RCOG Chickenpox in Pregnancy (Green-top Guideline No.13). Last reviewed 2024.

Background Information

Both chickenpox and shingles are caused by varicella-zoster virus (VZV) (human herpesvirus 3):
  • Chickenpox = primary VZV infection 
  • Shingles (herpes zoster) = reactivation of VZV from sensory nerve root ganglia, following primary infection

Maternal consequences:
  • Pneumonia
  • Hepatitis
  • Encephalitis 

Fetal / baby consequences:
  • Spontaneous miscarriage (only in 2nd and 3rd trimester)
  • Fetal varicella syndrome (FVS)

The risk for FVS is highest if exposure is <20 weeks gestation​​​​​​.

Guidelines

Step 1: determine VZV immunity status
  • If the patient is uncertain or has no previous history of chickenpox → serology testing for VZV antibodies
  • If patient had previous chickenpox or +ve serology → immune to VZV → no further action (note this is not explicitly stated in the guidelines)

Step 2: treat pregnant women that is NOT immune to VZV and has signifiant exposure with PEP (post-exposure prophylaxis)

Choice of PEP:
  • 1st line: oral aciclovir / valaciclovir to be given 7-14 days post-exposure
  • 2nd line: IM VZIGVaricella-zoster immunoglobulin to be given within 10 days post-exposure

  • Symptomatic treatment and hygiene - to prevent secondary bacterial infection

Anti-viral therapy
  • Severe chickenpox → IV aciclovir
  • If present <24 hours after rash onset → oral aciclovir
    • RCOG states offer if >20 weeks gestation, and consider if <20 weeks gestation

Women should avoid contact with potentially susceptible individuals, e.g. other pregnant women and neonates, until the lesions have crusted over. This is usually about 5 days after the onset of the rash.

 

VZIGVaricella-Zoster immunoglobulin has no therapeutic benefit once chickenpox has developed, therefore it should not be used in pregnant women who DEVELOPS chickenpox. It is only used in chickenpox / shingles EXPOSURE.

References

Author: Adams Lau
Reviewer:
Last Edited: 24/02/25