What is the management of Herpes Simplex Virus (HSV) infection in pregnancy?

From the Guidelines

Women with a history of genital herpes should receive suppressive therapy with acyclovir (400 mg three times daily) or valacyclovir (500 mg twice daily) starting at 36 weeks’ gestational age to reduce the risk of viral shedding, recurrences, and cesarean deliveries. Managing herpes simplex virus (HSV) during pregnancy requires careful medical supervision to protect both mother and baby. According to the 2022 Clinical Infectious Diseases study 1, routine screening of pregnant women with HSV type-specific serologies is not recommended due to a lack of evidence for cost-effectiveness. Instead, pregnant women should be screened for a history of genital herpes.

Key considerations for managing HSV in pregnancy include:

• Suppressing viral shedding and recurrences with antiviral therapy
• Reducing the risk of cesarean deliveries
• Preventing transmission to the infant
• Monitoring for symptoms and reporting any signs of an outbreak
• Practicing good hygiene and using condoms to prevent transmission

The use of antiviral medications during pregnancy is considered safe, with acyclovir remaining a category B medication 1. However, a case-control study found an increased risk of gastroschisis among women who used antiherpes medications between the month prior to conception and the third month of pregnancy 1. Despite this, the benefits of antiviral therapy in preventing neonatal herpes and its serious complications outweigh the potential risks.

For women who acquire genital herpes during pregnancy, treatment with suppressive-dose acyclovir (400 mg three times daily) at week 36 may help prevent HSV recurrences requiring cesarean delivery at term 1. Regular prenatal visits are essential to monitor for symptoms, and women should immediately report any signs of an outbreak such as genital pain, tingling, or visible lesions. If a woman experiences an outbreak near delivery, a cesarean section is typically recommended to prevent transmission to the baby during vaginal birth.

From the FDA Drug Label

The risk of neonatal HSV infection varies from 30% to 50% for genital HSV acquired in late pregnancy (third trimester), whereas with HSV acquisition in early pregnancy, the risk of neonatal infection is about 1% A primary herpes occurrence during the first trimester of pregnancy has been associated with neonatal chorioretinitis, microcephaly, and, in rare cases, skin lesions. In very rare cases, transplacental transmission can occur resulting in congenital infection, including microcephaly, hepatosplenomegaly, intrauterine growth restriction, and stillbirth Co-infection with HSV increases the risk of perinatal HIV transmission in women who had a clinical diagnosis of genital herpes during pregnancy.

Management of HSV in pregnancy involves considering the risks associated with untreated herpes simplex during pregnancy, including neonatal HSV infection, congenital infection, and perinatal HIV transmission.

• The risk of neonatal HSV infection is higher if the infection is acquired in late pregnancy.
• Primary herpes occurrence during the first trimester can lead to severe complications, including neonatal chorioretinitis, microcephaly, and skin lesions.
• Transplacental transmission can occur, resulting in congenital infection.
• Co-infection with HSV increases the risk of perinatal HIV transmission. Given the potential risks, management of HSV in pregnancy should be done under the guidance of a healthcare provider, and may involve antiviral therapy, such as valacyclovir, to reduce the risk of transmission and complications 2.

From the Research

Diagnosis and Prevention of Genital Herpes in Pregnancy

• Genital herpes lesions during pregnancy in a woman with a history of genital herpes is a recurrence, and there is no need for virologic confirmation 3
• In pregnant women with genital lesions who report they have not previously had genital herpes, virological confirmation by PCR and identifying the specific IgG type is necessary 3
• The risk of HSV seroconversion during pregnancy is 1-5% 3
• Antiviral prophylaxis should be offered to women with either a first or recurrent episode of genital herpes during pregnancy from 36 weeks of gestation until delivery 3, 4, 5

Treatment of Genital Herpes in Pregnancy

• A first episode of genital herpes during pregnancy should be treated with aciclovir (200 mg 5 times daily) or valaciclovir (1000 mg twice daily) for 5-10 days 3
• Recurrent herpes during pregnancy should be treated with aciclovir (200 mg 5 times daily) or valaciclovir (500 mg twice daily) 3
• Acyclovir prophylaxis beginning at 36 weeks' gestation is effective in reducing clinical HSV recurrences at the time of delivery, cesarean deliveries for clinical recurrence genital herpes, and the risk of HSV viral shedding at delivery 4

Mode of Delivery and Neonatal Herpes

• The risk of neonatal herpes is estimated at between 25% and 44% if a non primary and primary first genital herpes episode is ongoing at delivery, and 1% for a recurrence 3
• A cesarean delivery is recommended if a first episode of genital herpes is suspected (or confirmed) at the onset of labor, or if it occurred less than 6 weeks before delivery 3, 6
• When a recurrence of genital herpes is underway at the onset of labor, cesarean delivery is most likely to be considered when the membranes are intact and vaginal delivery in cases of prolonged rupture of membranes 3
• Any newborn with suspected neonatal herpes should be treated with intravenous acyclovir (20 mg/kg 3 times daily) before the PCR results are available 3