Most mothers of infants who acquire neonatal herpes lack histories of clinically evident genital herpes. The risk for transmission to the neonate from an infected mother is high (30%--50%) among women who acquire genital herpes near the time of delivery and is low (<1%) among women with histories of recurrent herpes at term or who acquire genital HSV during the first half of pregnancy. Because recurrent genital herpes is more common than initial HSV infection during pregnancy, the proportion of neonatal HSV infections acquired from mothers with recurrent herpes remains high. Prevention of neonatal herpes depends both on preventing acquisition of genital HSV infection during late pregnancy and avoiding exposure of the infant to herpetic lesions during delivery.
Women without known genital herpes should be counseled to avoid sex during the third trimester with partners known or suspected of having genital herpes. Pregnant women without known orolabial herpes should be advised to avoid cunnilingus during the third trimester with partners known or suspected to have orolabial herpes. Some specialists believe type-specific serologic tests are useful to identify pregnant women at risk for HSV infection and to guide counseling with regard to the risk of acquiring genital herpes during pregnancy. Such testing and counseling may be especially important when a woman's sex partner has HSV infection.
All women should be asked whether they have a history of genital herpes. At the onset of labor, all should be questioned carefully about symptoms of genital herpes, including prodrome, and all should be examined carefully for herpetic lesions. Women without symptoms or signs of genital herpes or its prodrome can deliver vaginally. Most specialists recommend that women with recurrent genital herpetic lesions at the onset of labor deliver by cesarean section to prevent neonatal herpes. Abdominal delivery does not completely eliminate the risk for HSV transmission to the infant. The results of viral cultures during pregnancy in women with or without visible herpetic lesions do not predict viral shedding at the time of delivery, and therefore routine viral cultures of pregnant women with recurrent genital herpes are not recommended.
Safety of systemic acyclovir, valacyclovir, and famciclovir therapy in pregnant women has not been established. Available data do not indicate an increased risk for major birth defects compared with the general population in women treated with acyclovir during the first trimester. These findings provide some assurance to women who have had prenatal exposure to acyclovir. Available data are insufficient to reach definitive conclusions regarding the risks to the newborn associated with acyclovir treatment during pregnancy. The experience with prenatal exposure to valacyclovir and famciclovir is too limited to provide useful information on pregnancy outcomes.
Acyclovir may be administered orally to pregnant women with first episode genital herpes or severe recurrent herpes and should be administered IV to pregnant women with severe HSV infection. Some data suggest that acyclovir treatment late in pregnancy might reduce the frequency of c-sections among women who have recurrent genital herpes by diminishing the frequency of recurrences at term, and some specialists recommend such treatment. The risk for herpes is high in infants of women who acquire genital HSV in late pregnancy; such women should be managed in consultation with an HSV specialist. Some specialists recommend acyclovir therapy, some recommend routine c-section to reduce the risk for neonatal herpes, or both.
