IntroductionDealing with genital herpes during pregnancy can be extremely stressful, because of the possibility of severe consequences if a child becomes infected with the herpes virus during labor or shortly after being born. Neonatal herpes can be deadly, and so women are often counseled toward very conservative management of their pregnancy and delivery options.
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 children women who become infected with herpes during their pregnancy, especially those who get infected 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 an greater risk of giving their infants neonatal herpes than women with HSV-2.
Risk Reduction Techniques
Doctors generally recommend suppressive therapy for all pregnant women with HSV infections starting at 36 weeks of pregnancy. Also a c-section is 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. The vast majority happen during birth.
Deciding What To Do
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.
I was recently asked the following question (paraphrased):
I know that suppressive therapy can reduce the risk of outbreaks during pregnancy, but I'm still worried about infecting my infant. Since the herpes virus can be present in my body when no outbreak is present, is it ever safe to schedule a vaginal deliver when you have genital herpes during pregnancy? What if I am about to have an outbreak? How often is virus present before symptoms appear
There are several issues that need to be addressed to answer this woman's concerns:
- Can doctors screen for the herpes virus when there is no outbreak present?
- Does having detectable levels of herpes in genital secretions at the time of delivery reliably predict the risk of neonatal herpes transmission?
- How often is virus present in the genital secretions when there is no outbreak, or right before an outbreak?
- How common are breakthrough outbreaks when a woman is on suppressive therapy during her pregnancy?
- Are c-sections an effective way to reduce the risk of neonatal herpes transmission during delivery?
Can doctors detect herpes during pregnancy?
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 predicting herpes shedding at the time of birth.
In addition, current ACOG guidelines recommend against routine herpes testing during pregnancy.
Is having detectable virus levels clearly associated with neonatal herpes infection?
A large 2005 study of more than 40,000 deliveries where HSV cultures were taken found that neonatal herpes was extraordinarily rare in women who were not culture positive at the time of delivery. Where 5 percent of women who were positive for HSV gave birth to infants with neonatal herpes, only 0.02 percent of women who were culture negative did. That's six infants out of 39,821 deliveries. Furthermore, when samples from two of those women were re-tested, they were both found to contain HSV DNA.
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.
How often do people with herpes shed the virus even when they don't have an outbreak?
A large 2011 study, published in JAMA, investigated how often people with asymptomatic herpes infections shed virus and how much virus they shed. The researchers, who looked at 500 people with herpes over a period of 15 years, 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. (It is also worth noting that some people who believed they had no herpes symptoms did have lesions that were detectable by researchers.)
Continued in Part II: Evaluating specific interventions for reducing neonatal herpes
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