Maternal primary infection with HSV before pregnancy does not usually impact the intrauterine development of the fetus. Increased rates of miscarriage and IUGR following primary HSV infection during pregnancy have been reported.
Intrauterine HSV infections are rare (1 in 200,000 deliveries). Manifestations in such cases include skin vesicles, eye disease, microcephaly or hydranencephaly. The greatest risk to infants exposed perinatally to HSV is the development of neonatal herpes infection. There are three categories of neonatal HSV infections: local (skin, eye and mouth) disease, encephalitis, and disseminated infection. There is significant neonatal mortality with disseminated disease (60 percent), and a neonatal mortality rate of 15 percent with encephalitis. Neonatal HSV infection is treated with intravenous acyclovir.
Neonatal HSV infection complicates approximately 1 in 3,500 deliveries. The estimated risk of neonatal HSV during primary maternal infection is 50 percent, and in cases of recurrent HSV infection, the risk of neonatal HSV ranges from 0 to 3 percent. Thus, neonatal HSV infection is most often caused by primary maternal HSV infection, rather than recurrent infection. Factors predicting neonatal HSV transmission include : cervical HSV shedding, invasive monitoring, preterm delivery, maternal age less than 21 years of age, and HSV viral load.
Elective cesarean delivery is recommended for women with demonstrable genital herpes lesions or prodromal symptoms in labor to reduce the incidence of neonatal HSV infection. The risk of neonatal HSV infection in cases of nongenital, maternal HSV lesions (thigh, buttock, mouth) is low; therefore, cesarean delivery is not recommended for these women.
Neuraxial Analgesia: Parturients with primary and untreated Herpes Simplex infections are usually not candidates for neuraxial analgesia. CNS translocation of HSV does not typically occur with routine infection; therefore, any breach of the CNS during neuraxial analgesia would bring the risk of introducing virus into the CSF which was not there before.
Parturients with reactivation or treated primary HSV infection are candidates for neuraxial analgesia, due to the absence of HSV viremia.
Primary or recurrent HSV infection during pregnancy:
- Acyclovir 400 mg TID for 7-10 days or Valacycovir 1000 mg BID for 7-10 days
Pregnant women who have 2 or more HSV recurrences a year are candidates for prophylaxis:
- Acyclovir 400mg BID or Valacyclovir 500-1000 mg daily