In a patient with suspected vesicles in the vaginal canal indicating possible herpes simplex virus (HSV) infection, should a vaginal birth be proceeded with or should the mother be given antiviral medication, such as acyclovir (antiviral medication), to prevent transmission to the newborn?

Management of Suspected Genital Herpes Lesions at Labor Onset

If vesicles are present in the vaginal canal at the onset of labor, proceed with cesarean delivery rather than administering antiviral medication alone, as the risk of neonatal transmission is substantial (5% overall, up to 30-50% for primary infections) and cesarean section reduces transmission risk by approximately 85%. 1, 2

Immediate Assessment at Labor Onset

At the onset of labor, perform a careful examination and questioning about genital herpes symptoms 1:

• Examine for visible vesicles, ulcers, or prodromal symptoms in the vaginal canal, cervix, and external genitalia 1
• Determine if this represents a first episode versus recurrent disease by asking about prior history of genital herpes 1
• Assess timing - when symptoms first appeared relative to delivery 1

Decision Algorithm for Mode of Delivery

When Cesarean Delivery is Indicated:

Cesarean delivery is recommended in the following scenarios 1, 3:

• First episode (primary or non-primary) of genital herpes at labor onset - transmission risk is 30-50% 1
• First episode occurring within 6 weeks of delivery 3
• Visible genital herpes lesions or prodrome at labor onset, regardless of recurrent versus primary status 1
• Premature rupture of membranes at term with active first episode 3

When Vaginal Delivery May Be Considered:

Vaginal delivery may be considered only when 1:

• No symptoms or signs of genital herpes infection or prodrome are present at labor onset 1
• Recurrent herpes with prolonged rupture of membranes (though cesarean is still preferred with intact membranes) 3

The transmission risk with recurrent herpes at delivery is only 1-3%, compared to 30-50% for primary infections 1, 3.

Role of Antiviral Medication

Antiviral therapy at labor onset does NOT replace cesarean delivery when lesions are present:

• Acyclovir given at the time of labor does not adequately prevent neonatal transmission when active lesions are present 1
• The standard of care remains cesarean delivery for visible lesions at labor 2
• Cesarean delivery reduces transmission by 85% (from 7.7% to 1.2%) when HSV is being shed 2

When Antivirals Should Have Been Used (But Too Late Now):

Suppressive antiviral therapy should have been initiated at 36 weeks gestation in women with a history of genital herpes during pregnancy 1, 3:

• Acyclovir 200 mg orally 5 times daily OR valacyclovir 500-1000 mg twice daily 3
• This reduces clinical recurrences at delivery and decreases cesarean rates 1
• However, routine suppression was not recommended in the 1998 CDC guidelines for women with only a history of recurrent herpes 1

Critical Pitfalls to Avoid

Do not rely on viral cultures during pregnancy to predict shedding at delivery - they have no predictive value and should not be performed routinely 1

Do not assume cesarean delivery completely eliminates transmission risk - it reduces but does not eliminate risk 1

Do not delay decision-making - cesarean delivery is most effective when performed before prolonged rupture of membranes 3, 2

Neonatal Management After Exposure

All infants exposed to HSV during birth must be followed carefully 1:

• Obtain surveillance cultures of mucosal surfaces 24-48 hours after birth 1
• Do NOT routinely treat asymptomatic exposed infants with acyclovir - the risk is low for most infants 1
• Exception: Infants born to women with primary infection near term are high-risk and some experts recommend empiric acyclovir therapy 1
• Any infant with evidence of neonatal herpes should receive IV acyclovir 20 mg/kg three times daily immediately 4, 3

Key Distinction: Primary vs Recurrent Disease

The timing and type of maternal infection dramatically affects transmission risk 1, 2:

• Primary infection near delivery: 30-50% transmission risk 1
• Recurrent infection at delivery: 1-3% transmission risk 1, 3
• HSV-1 genital infection has higher transmission than HSV-2 (16.5-fold increased risk) 2
• First-episode infection increases risk 33-fold compared to recurrent disease 2

Bottom line: The presence of suspected vesicles at labor mandates cesarean delivery as the primary intervention to reduce neonatal morbidity and mortality, not antiviral medication alone. 1, 2