Use of antiviral drugs in late pregnancy for reducing the recurrence of genital herpes at labor and birth and reducing the risk of newborn HSV infection

The incidence of herpes, a sexually transmitted disease, varies across the world. Among pregnant women with herpes, nearly 75% can expect at least one flare-up during their pregnancy. Transmission of the virus from mother to baby typically occurs by direct contact with the virus during birth. It is often recommended that a cesarean should be offered to women with active lesions to reduce the risk of transmission to the baby. In addition, several antiviral agents are available for use both for therapy and for preventing a flare-up. These antiviral drugs include acyclovir, penciclovir, valacyclovir, and famciclovir. The review assessed whether antiviral drugs given to pregnant women with herpes before a recurrence might be effective in reducing transmission to the baby. Seven studies were identified involving 1249 women. Giving antiviral drugs reduces viral shedding and recurrences at labor and birth. They also reduced the use of cesarean, but there is no evidence of reduction in neonatal herpes. Women should also be informed that the risk of the baby getting herpes during birth is low.

Authors' conclusions: 

Women with recurrent genital herpes simplex virus should be informed that the risk of neonatal herpes is low. There is insufficient evidence to determine if antiviral prophylaxis reduces the incidence of neonatal herpes. Antenatal antiviral prophylaxis reduces viral shedding and recurrences at delivery and reduces the need for cesarean delivery for genital herpes. Limited information exists regarding the neonatal safety of prophylaxis. The risks, benefits, and alternatives to antenatal prophylaxis should be discussed with women who have a history and prophylaxis initiated for women who desire intervention.

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Background: 

Genital herpes simplex virus (HSV) infection is one of the most common viral sexually transmitted infections. The majority of women with genital herpes will have a recurrence during pregnancy. Transmission of the virus from mother to fetus typically occurs by direct contact with virus in the genital tract during birth.

Objectives: 

To assess the effectiveness of antenatal antiviral prophylaxis for recurrent genital herpes on neonatal herpes and maternal recurrences at delivery.

Search strategy: 

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (January 2007), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2006, Issue 4), MEDLINE (January 1966 to February 2007) and EMBASE (January 1974 to February 2007; handsearched conference proceedings; reviewed bibliographies of all relevant articles for further references; and contacted experts in the field.

Selection criteria: 

Randomized controlled trials which assessed the effectiveness of antivirals compared to placebo or no therapy, on neonatal herpes and maternal disease endpoints among pregnant women with genital herpes.

Data collection and analysis: 

Two authors independently applied study selection criteria and extracted data.

Main results: 

Seven randomized controlled trials (1249 participants) which met our inclusion criteria compared acyclovir to placebo or no treatment (five trials) and valacyclovir to placebo (two trials). The effect of antepartum antiviral prophylaxis on neonatal herpes could not be estimated. There were no cases of symptomatic neonatal herpes in the included studies in either the treatment or placebo groups. Women who received antiviral prophylaxis were significantly less likely to have a recurrence of genital herpes at delivery (relative risk (RR) 0.28, 95% confidence interval (CI) 0.18 to 0.43, I2 = 0%). Women who received antiviral prophylaxis were also significantly less likely to have a cesarean delivery for genital herpes (RR 0.30, 95% CI 0.20 to 0.45, I2 = 27.3%). Women who received antiviral prophylaxis were significantly less likely to have HSV detected at delivery (RR 0.14, 95% CI 0.05 to 0.39, I2 = 0%).