Treatment of Varicella Zoster Infection in Pregnant Women
For pregnant women with varicella (chickenpox) infection, varicella zoster immune globulin (VZIG) should be administered within 96 hours of exposure for susceptible women, and oral acyclovir 800 mg 5 times daily should be given for active infection, with intravenous acyclovir 10-15 mg/kg every 8 hours for severe cases or complications such as pneumonitis.
Prevention in Susceptible Pregnant Women
For pregnant women exposed to varicella who are susceptible (no history of chickenpox or vaccination, or seronegative):
- VZIG should be administered as soon as possible but within 96 hours after exposure to varicella 1
- If VZIG is unavailable or administration is delayed beyond 96 hours, oral acyclovir can be considered as prophylaxis 2, 3
- Recent evidence suggests oral acyclovir may be equally effective to VZIG in preventing maternal chickenpox (30.8% vs 36.6% developed chickenpox, p=0.32) 3
Treatment of Active Varicella Infection
For pregnant women who develop varicella infection:
Mild to Moderate Disease:
- Oral acyclovir 800 mg 5 times daily for 7-10 days 4, 5
- Treatment should be started within 24-72 hours of rash onset for maximum effectiveness
Severe Disease or Complications:
- Intravenous acyclovir 10-15 mg/kg every 8 hours for 5-10 days 5
- Hospital admission should be strongly considered for pregnant women who develop varicella pneumonitis 5
Monitoring and Follow-up
- Detailed ultrasound and appropriate follow-up is recommended for all women who develop varicella in pregnancy to screen for fetal consequences of infection 5
- Women who develop varicella in the first or second trimester should be counseled about the 0.5-1.5% risk of congenital varicella syndrome 6
Special Considerations for Peripartum Infection
If maternal varicella develops within 5 days before or 2 days after delivery:
- The newborn should receive VZIG immediately 5, 6
- Neonatal healthcare providers should be informed to optimize early neonatal care 5
- Intravenous acyclovir should be given to babies presenting unwell with chickenpox 2
Dosage Adjustments
For pregnant women with renal impairment, acyclovir dosage should be modified based on creatinine clearance:
- CrCl >25 mL/min: 800 mg every 4 hours, 5 times daily
- CrCl 10-25 mL/min: 800 mg every 8 hours
- CrCl 0-10 mL/min: 800 mg every 12 hours 4
Important Caveats
- Varicella vaccine should not be administered during pregnancy due to the potential risk of fetal infection 1, 5
- Breastfeeding is encouraged for babies infected with or exposed to VZV 2
- A mother with chickenpox does not need to be isolated from her own baby 2
- Unlike primary varicella infection, herpes zoster (shingles) during pregnancy has not been documented to cause complications unless in disseminated form 6
This approach prioritizes maternal and fetal health outcomes while providing clear guidance on prevention and treatment strategies for varicella zoster infection during pregnancy.