HSV in pregnancy

Background

• Infection with herpes simplex virus during pregnancy

Epidemiology

• Risk of perinatal transmission varies by maternal serostatus relative to the active infection at the time of delivery
  • Newly acquired
    • First-episode primary infection (mother has no serum antibodies to HSV-1 or -2 at onset): risk of transmission is about 60%
    • First-episode nonprimary infection (mother has a new infection with one HSV type in the presence of antibodies to the other type): risk of transmission is less than 30%
  • Recurrent (mother has pre-existing antibodies to the HSV type that is isolated from the genital tract): risk of transmission is less than 2%

Serology	Infected with	Risk of perinatal transmission	Neonatal HSV per 100,000 births
Negative	HSV-1 or -2	60%	54
HSV-1 only	HSV-2	≤30%	26
HSV-2 only	HSV-1		35
HSV-1 + HSV-2	HSV-1 or -2	≤2%	12
HSV-2 ± HSV-1			22

Clinical Manifestations

• If acquired during pregnancy, HSV can cause spontaneous abortion and should be treated for 7 to 10 days
• Can also cause congenital HSV in the fetus

Management

• If HSV-2-positive, then if there are lesions or PCR-positivity at time of labour, could consider Cesarean section
• For the management of the neonate post-partum, refer to neonatal HSV