Genital herpes simplex virus (HSV) infection is one of the most common sexually transmitted infections, occurring in one in five women in the United States. This is a major health concern because women who have genital herpes infection during pregnancy are at risk of transmitting the virus to the developing fetus and newborn. Most persons infected with HSV are unaware they have contracted it, and approximately 80 percent of infants with HSV are born to mothers who have no reported history of infection. HSV type 1 causes approximately one third to one half of neonatal herpes cases, and up to 80 percent of new genital herpes infections among all women may be caused by HSV type 1. The American College of Obstetricians and Gynecologists (ACOG) has released a practice bulletin to outline the spectrum of maternal and neonatal genital herpes infection and to provide guidelines on managing the infection during pregnancy.

Viral or serologic testing should be performed to confirm suspected HSV infections; the basic groups of tests used are viral and antibody detection techniques. For viral detection, the primary testing techniques are viral culture and HSV antigen detection by polymerase chain reaction. The presence of antibodies to either HSV type 1 or 2 can be detected with laboratory-based and point-of-care serologic tests. The ACOG bulletin does not recommend routine antepartum genital HSV culture collection in asymptomatic women with recurrent disease or routine HSV screening of pregnant women.

During pregnancy there is a higher risk of perinatal transmission with primary HSV infection than with recurrent infection. If a primary HSV outbreak is diagnosed in pregnancy, oral antiviral treatment may be administered to help reduce the duration and severity of symptoms and viral shedding. Antiviral agents commonly used to treat HSV infections are acyclovir (Zovirax), famciclovir (Famvir), and valacyclovir (Valtrex), which are all U.S. Food and Drug Administration pregnancy category B medications. For patients with more severe HSV infection, oral treatment can be used for more than 10 days if the lesions have not healed completely. Intravenous administration of acyclovir may be beneficial for pregnant women with severe genital HSV infection or disseminated herpetic infections. For pregnant women with active recurrent genital herpes, suppressive viral therapy should be offered at or beyond 36 weeks' gestation.

Transabdominal invasive procedures (e.g., chorionic villus sampling, amniocentesis, percutaneous umbilical cord blood sampling) may be performed on pregnant women with recurrent HSV infection, even when genital lesions are present. Invasive monitoring (e.g., fetal scalp electrodes) markedly increases the risk of neonatal infection compared with external monitoring; however, if fetal scalp monitoring is indicated, it may be reasonable in women with a history of recurrent HSV and no active lesions. Cesarean delivery is recommended to prevent perinatal HSV transmission in women with active genital lesions or prodromal symptoms, but it is not recommended for women with HSV lesions found only on nongenital areas, such as the back, thigh, or buttock. Breastfeeding is not contraindicated unless there is a lesion on the breast.