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

• Typical lesions of genital herpes
• Can cause congenital HSV in the fetus

Management

• If acquired during pregnancy, can be treated for 7 to 10 days if severe
• Cesarean section should be offered in the following scenarios:
  • Prodromal symptoms or active lesions at the time of delivery
  • First-episode genital herpes in the third trimester
• Women with recurrent genital herpes should be offered acyclovir or valacyclovir starting at 36 weeks gestation
• For the post-partum management of the neonate, refer to neonatal HSV

Further Reading

• SOGC Guidelines for the Management of Herpes Simplex Virus in Pregnancy. J Obstet Gynaecol Can. 2017;39(8):e199-e205. doi: 10.1016/j.jogc.2017.04.016