Background Information

Chickenpox and Shingles

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

Complications

Maternal consequences:

• Pneumonia
• Hepatitis
• Encephalitis

Fetal / baby consequences:

• Spontaneous miscarriage (only in 2nd and 3rd trimester)

• Fetal varicella syndrome
  • Risk is highest following maternal infection during the first 20 weeks (low risk >20 weeks)
  • Characterised by several congenital anomalies  

• Neonatal varicella
  • May occurs if maternal infection occurs in the month before delivery
  • Maternal infection from 5 days before to 2 days after delivery has the highest risk of severe, disseminated infection

• Shingles in infancy
  • Due to reactivation of latent VZV acquired either in utero (asymptomatic or minimally symptomatic infection) or postnatally.
  • It presents as a dermatomal vesicular eruption, usually within the first year of life.

Guidelines

Chickenpox / Shingles Exposure in Pregnancy

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 but assumed)

Step 2: treat pregnant women who are NOT immune to VZV and have significant 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 VZIG to be given within 10 days post-exposure

Pregnant Women Who Develop Chickenpox

• Symptomatic treatment and hygiene – to prevent secondary bacterial infection

Anti-viral therapy

• Severe/complicated chickenpox  → IV aciclovir
• Uncomplicated chickenpox presenting <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.

References

Original Guideline