Contributor: John Dacus, MD, Sharon Keiser, MD
Last Update: 4/25/2016
Genital Herpes Simplex Virus (HSV) infection is one of the most common sexually transmitted diseases in the U.S. There are estimated to be 45 million people infected with genital herpes. Most genital infections are caused by HSV type 2 but type 1 infections are becoming more frequent causes of genital infection.
Genital Herpes is transmitted by direct sexual contact. The risk of acquiring HSV infection is related to frequency of intercourse, race, age of patient, and number of sexual partners.
Transmission of HSV may occur transplacentally or by neonatal contact with the virus during vaginal delivery. The risk of transmission is dependent on whether the disease is primary, non-primary first episode or recurrent. Primary is defined as the first episode of genital herpes with no pre-existing antibodies against HSV-1 or HSV-2. Non-primary first episode occurs when antibodies against either HSV-1 or HSV-2 are already present and the current infection is caused by the opposite HSV. Recurrent HSV genital infection already shares antibodies against the current HSV infection.
The gold standard for diagnosing genital herpes is viral culture which can be reported as HSV-1 or HSV-2. If vesicles are present they should be unroofed prior to culturing to increase sensitivity. A more sensitive technique is virus type specific DNA PCR. Serologic testing may also be used which may help distinguish primary infection from recurrent infection by the presence of IgM antibodies. Clinically the picture may vary; from minimal symptoms to very painful vesicular lesions and even lymphadenopathy. Rarely, hepatitis and encephalitis may occur.
The neonate can be infected transplacentally, intrapartum, or postpartum. More than 70% of infants who acquire herpetic infection are born to mothers who have no symptoms and no detected lesions at delivery. Approximately 5% of symptomatic infants in the nursery will have acquired herpetic infection transplacentally, almost all of which are associated with primary infection with HSV-2.
Transmission at the time of vaginal delivery occurs when the fetus passes through the birth canal and comes in contact with the virus. The risk is 50% when the infection is primary, 33% when the infection is non-primary first episode, and less than 4% with recurrent infections. Seventy percent of neonatal herpetic infections are caused by HSV-2. Most neonatal infections caused by HSV-1 are associated with primary HSV-1 maternal infections acquired late in pregnancy.
The infected neonate may exhibit central nervous system lesions, microcephaly, hydranencephaly, microphthalmia, vesicular rash, chorioretinitis, and mouth lesions.
Management in Pregnancy
Confirmation of genital herpes infection should be documented by viral culture or DNA PCR technique when lesions are present. Until 1988 serial viral cultures were obtained late in pregnancy, but this is no longer recommended.
The American College of Obstetricians and Gynecologists now recommends vaginal delivery if no lesions are visible and no prodromal symptoms present at the onset of labor. Also there is no duration of membrane rupture which would preclude offering cesarean section in the presence of active disease. If primary disease occurs within 3 weeks of labor, it is reasonable to offer cesarean section even when no lesions are identified.
Premature rupture of membranes prior to 32 weeks of gestation should be handled conservatively and betamethasone administered. After 32 weeks of gestation in the presence of active herpes infection, it is probably reasonable to proceed with cesarean section.
Anti-viral Therapy for Herpes
• Primary or first-episode infection: Acyclovir 400 mg po tid for 7-10 days.
• Symptomatic recurrent episode: Acyclovir 400 mg po tid for 5 days.
• Daily suppression: Acyclovir 400mg po tid from 36 weeks
• Severe disseminated disease: Acyclovir 5-10 mg/kg IV q 8 hours for 2-7 days, then po to complete therapy for 10 days.
Prophylaxis can be considered in all women with a history of recurrent genital herpes. Women with only one single outbreak of genital herpes, or a remote history of a genital herpes outbreak do not require prophylaxis. If a patient has not experienced a recurrent genital herpetic infection during the current pregnancy, usually no suppressive antiviral therapy is indicated at 36 weeks. Women who are seropositive for either HSV-1 or HSV-2, but do not have a history of genital herpetic lesions, do not require prophylaxis.
HSV on Pap Smear
The rare patient will have HSV reported on the pap smear which has a fairly sensitive association with active herpes lesions. These patients need to be told that they were shedding virus at the time of the pap smear collection. They should be advised to use condoms to protect their partners. They should be offered acute treatment based on the personal history of lesions as outlined above. If there is no personal history of HSV, collect HSV1 and HSV2 IgM and IgG titers so we can determine whether this represents a primary episode or recurrence. This should be considered an outbreak in pregnancy and the patient should receive prophylaxis at 36 weeks.
1. Hill J, Robert S. Herpes simplex virus in pregnancy: new concepts in prevention and management. Infect Drs. In Preg 2005; 32:657-670.
2. Sexually transmitted diseases treatment guidelines, 2010. Genital HSV infections: 20-24
3. ACOG compendium 2008. Practice Bulletin No. 57: 1214-1220.
4. Bernstein H. Maternal and perinatal infection-viral. Obstetrics: normal and problem pregnancies, 2007; 5th ed:1219-1221