What is the recommended treatment for pregnant women diagnosed with chickenpox, specifically regarding the use of acyclovir?

Acyclovir Treatment for Pregnant Women with Chickenpox

Pregnant women with chickenpox should receive oral acyclovir if they present within 24 hours of rash onset, particularly those at risk for moderate to severe disease. 1

Indications for Acyclovir in Pregnancy

• Acyclovir is indicated for pregnant women at increased risk for moderate to severe varicella infection 1
• Risk factors that warrant acyclovir treatment include:
  • Presentation within 24 hours of rash onset (optimal timing for effectiveness) 1, 2
  • Second or third trimester of pregnancy 3
  • Presence of respiratory symptoms or signs of complicated disease 3

Dosing and Administration

• For oral treatment of uncomplicated varicella in pregnancy:
  • 800 mg orally five times daily for 5 days 2
  • Treatment should be initiated as soon as possible, ideally within 24 hours of rash onset 1, 2
• For severe or complicated varicella (e.g., pneumonitis):
  • Intravenous acyclovir 10-15 mg/kg every 8 hours for 5-10 days 3
  • Hospitalization should be strongly considered 3

Safety in Pregnancy

• Acyclovir is classified as FDA Category B in pregnancy, indicating relative safety 1, 4, 5
• A registry of 596 infants exposed to acyclovir during first trimester showed no increased rate of birth defects compared to the general population 1, 5
• No pattern of adverse pregnancy outcomes has been reported after acyclovir exposure 6

Effectiveness

• Acyclovir reduces severity of symptoms and accelerates healing when started within 24 hours of rash onset 1, 2
• Five days of therapy is sufficient; longer courses provide no additional benefit 2
• Recent evidence suggests oral acyclovir may be as effective as varicella zoster immune globulin (VZIG) in preventing maternal chickenpox after exposure 7

Alternative Prevention Strategies

• For susceptible pregnant women exposed to varicella who have not yet developed symptoms:
  • VZIG should be administered within 96 hours of exposure 6, 8
  • If VZIG is unavailable or exposure was >96 hours ago, oral acyclovir prophylaxis can be considered 9

Special Considerations

• For peripartum varicella (maternal rash 5 days before to 2 days after delivery):
  • The newborn should receive VZIG immediately 3, 10
  • Inform neonatal healthcare providers about the exposure 3
• For pregnant women with varicella pneumonia:
  • Prompt hospitalization and IV acyclovir are essential 3, 10
  • This is a potentially life-threatening condition requiring aggressive treatment 10

Important Caveats

• Acyclovir does not reduce transmission of varicella or duration of absence from school/work 1
• Viral resistance to acyclovir has not been documented with short-term therapy for chickenpox 2
• Adequate hydration must be maintained during acyclovir treatment to prevent renal complications 4