Is Vaginal Birth Safe For Women With Genital Herpes?

Dealing with genital herpes during pregnancy can be extremely stressful. There can be severe consequences if a child becomes infected with the herpes virus during labor or shortly after being born. And neonatal herpes can be deadly. Because of this, women with genital herpes are often counseled toward a very conservative management of their pregnancy and delivery options.

But not all pregnant women with genital herpes are at equal risk of transmitting the virus to their infant. The risk of neonatal herpes is highest, by far, for women who become infected with herpes during their pregnancy, especially near the end of their pregnancy.

Transmission rates are substantially lower for women who have been infected for a long period of time, even if they have an active infection during the course of their pregnancy. There is also some data that women with genital HSV-1 infections may have a greater risk of giving their infants neonatal herpes than women with HSV-2.

Doctors generally recommend suppressive therapy for all pregnant women with HSV infections starting at 36 weeks of pregnancy. A c-section is also recommended if they have an active genital herpes outbreak near their time of delivery.

The suppressive therapy is to reduce the risk of an outbreak and lower viral shedding. The c-section is performed in order to reduce the chance that the infant will be exposed to the virus while passing through the birth canal.

Only a small percentage of neonatal herpes transmissions occur during the pregnancy itself. The vast majority happen during birth.

Neonatal herpes is a scary prospect, and many pregnant women are understandably torn about their pregnancy management options, particularly if they are interested in having a more natural childbirth experience.

Also, some women worry about infecting their child even with suppressive therapy. After all, the herpes virus can be present in the body even when there is not currently an outbreak.

Although doctors can certainly test for viral DNA during pregnancy, there is some question about how useful these tests are, particularly when they're done more than a few days before birth. A 1999 study of herpes viral shedding during pregnancy found that while almost 60 percent of women who gave birth within two days of having a positive test were still positive during delivery, testing any earlier than that was largely inaccurate at predicting herpes shedding at the time of birth.

In addition, current ACOG guidelines recommend against routine herpes testing during pregnancy.

A large 2005 study found that neonatal herpes was extraordinarily rare in women who were not culture positive at the time of delivery. Where five percent of women who were culture positive for HSV gave birth to infants with neonatal herpes, only 0.02 percent of women who were culture negative did. 

While it would be ideal if there were more large studies examining this question, it seems likely that detectable virus levels at the time of delivery is linked to neonatal herpes infection. Or, more accurately, it seems clear that not having detectable virus levels during delivery makes transmitting neonatal herpes highly unlikely.

A large 2011 study, published in JAMA, investigated how often people with asymptomatic herpes infections shed the virus and how much virus they shed. The researchers found that people with asymptomatic genital HSV-2 shed detectable levels of virus 10 percent of the time—about half as often as people with symptomatic infections. However, the amount of virus they shed was similar.