Is suppressive antiviral therapy necessary during pregnancy if there have been no recent herpes outbreaks and no outbreaks during pregnancy?

Suppressive Therapy in Pregnancy Without Recent or Current Outbreaks

Suppressive antiviral therapy is NOT routinely recommended during pregnancy if you have no recent outbreaks and no outbreaks during the current pregnancy. 1

Key Guideline Recommendations

The CDC explicitly states that "episodic therapy for first-episode HSV disease and for recurrences can be offered during pregnancy, but suppressive therapy is not used routinely" in pregnant women without frequent or severe recurrences. 1

When Suppressive Therapy IS Indicated in Pregnancy

Suppressive therapy during pregnancy should be reserved for specific clinical scenarios:

• Frequent, severe recurrences: If you have a documented history of frequent or severe recurrent genital HSV disease, acyclovir prophylaxis might be indicated. 1

• Late pregnancy suppression (≥36 weeks): For women with a history of genital herpes, suppressive therapy starting at 36 weeks gestation reduces HSV shedding at delivery and decreases the need for cesarean delivery. 2, 3

  • Valacyclovir 500 mg twice daily from 36 weeks until delivery reduces recurrent genital herpes requiring cesarean delivery from 13% to 4% (P=0.009). 3
  • This approach also reduces HSV detection by culture from 9% to 2% at delivery (P=0.02). 3

Clinical Decision Algorithm

For women with history of genital herpes but no recent/current outbreaks:

1. Before 36 weeks: No suppressive therapy needed unless you have frequent, severe recurrences (≥6 episodes per year). 1

2. At 36 weeks gestation: Consider initiating suppressive therapy (valacyclovir 500 mg twice daily) to reduce risk of outbreak at delivery and need for cesarean section. 2, 3

3. If outbreak occurs during pregnancy: Treat with episodic therapy (acyclovir 400 mg three times daily for 5-10 days). 2

4. At labor onset: If visible lesions or prodromal symptoms present, cesarean delivery is recommended regardless of prior suppressive therapy. 1, 2

Safety Considerations

• Acyclovir is the first-choice antiviral for HSV infections in pregnancy based on decades of safety data showing no pattern of adverse pregnancy outcomes. 1, 4

• Clinical data over several decades with valacyclovir and acyclovir have not identified a drug-associated risk of major birth defects. 4

• The risk of neonatal HSV transmission is low (about 1%) with HSV acquisition in early pregnancy, but increases to 30-50% if genital HSV is acquired in the third trimester. 4

Important Caveats

The primary goal is preventing neonatal transmission, which occurs mainly through maternal genital shedding at delivery, not through transplacental transmission. 1 Therefore:

• Asymptomatic viral shedding can still occur even without visible outbreaks. 2, 5

• The decision for late pregnancy suppression (≥36 weeks) should balance the proven reduction in cesarean delivery rates against the low baseline risk of transmission in women with recurrent (not primary) HSV-2. 3

• HIV-infected pregnant women may have different considerations, though specific data on suppressive therapy to reduce HIV/HSV co-transmission is lacking. 1