Genital Herpes and Pregnancy: Preventing Neonatal Transmission: Genital Herpes and Pregnancy Overview

The incidence of genital herpes is mentioned on this slide. It's approximately 1 million new cases of genital herpes per year in the United States. This information is gathered, as you can see, by the references from several places, and it's based on testing individuals over the age of 12 for antibody to HSV-2, which defines them as having genital herpes. So, in the United States currently, there are approximately 45 million individuals with genital herpes; and again, approximately 1 million new cases are acquired in the United States each year.

Let us turn to Slide 5. Genital herpes has many ramifications. One of the most important is that it's associated with an increased risk of HIV, and so there's a direct correlation between being antibody positive for HSV-2, which defines the individual as having genital herpes, and acquiring HIV from an individual [with] whom they have sexual contact.

Certainly there are psychological, social, and medical concerns when someone contracts genital herpes, and there's a major impact on social health. Almost 90% of those who have the disease express significant concern about transmitting this infection to their sexual partner. And, finally, what we'll concentrate on today is the transmission of herpes to the newborn during pregnancy at around the time of delivery.

There's a rough estimate that genital herpes occurs in approximately 1 in 3200 live births, and certainly there can be significant, serious morbidity and mortality associated with this infection in the newborn. There can be certainly mental retardation, learning disabilities, seizure disorders, numerous other central nervous system problems, and a significant degree of mortality when this infection is transmitted and occurs in the newborn period.

Let us turn to Slide 6. This is an example -- a slide provided to me by Dr. Whitley, who's a pediatrician in Alabama. Most newborns infected with genital herpes are delivered to women who have asymptomatic or unrecognized disease. So the concept and the focus that we all adhere to is that we ask and see which patients have genital herpes. But in reality, it's the patient who doesn't know she's infected, doesn't know that she's susceptible to infection, that we're not assessing or looking for; and, therefore, in this individual the risk of acquiring herpes and transmitting herpes to the newborn is real.

The next slide, Slide 7, demonstrates this -- that there is a significant number of individuals who have unrecognized genital herpes. This pie chart looks at approximately 100 patients who have antibody to HSV-2. If you ask the patient, "Have you been diagnosed with genital herpes?," only approximately 20% truly know that they have genital herpes. The other 80% are unaware of their infection. So antibody testing is the specific way of diagnosing this infection and making the patient aware that [he or she is] infected.

In this study of those 80 patients, they were followed for several months; they were examined frequently and taught how to recognize this infection. Sixty-percent truly had clinical recurrences of herpes that were undiagnosed, and another 20% were asymptomatic.

So, in both these populations, the strongest way of diagnosing this infection -- perhaps the only way of diagnosing this infection -- is with the newer antibody techniques that differentiate HSV-1 from HSV-2.

Let us move to Slide 8. This study reported in The New England Journal of Medicine a few years ago really confirms that most genital herpes patients will shed virus asymptomatically. And what we're saying is that an individual who is antibody positive to HSV-2, whether they have a history of symptomatic infection (which is the pie chart on your right) or whether they give you no reported history of symptomatic genital herpes, will over a period of time shed virus from the genital tract in the absence of lesions.

This study was performed on approximately 150 patients. They were followed and sampled with cultures and PCR [polymerase chain reaction] for approximately 90 days. And during that time period, 61% of those individuals with symptomatic disease, but also 68% of those with no history of symptomatic genital herpes, shed virus asymptomatically. So the patient who has antibody to herpes sheds virus at similar rates as the patient who has antibodies but does present with clinical outbreaks.

Moving on to Slide 9. Genital herpes complicating pregnancy -- as I've tried to demonstrate in the previous slide -- is most commonly asymptomatic; so the pregnant woman doesn't know that she's infected or doesn't know that she's susceptible to infection. Several studies clearly show that the healthcare provider needs to be careful in diagnosing herpes, either primary or recurrent disease, just by clinical presentation alone.

And so, during pregnancy, a recurrence can appear very severe and may be diagnosed as a primary infection; and perhaps a primary infection can be very mild and missed and diagnosed as recurring disease.

Moving on to Slide 10, several recent studies clearly demonstrate factors influencing the fetus or the newborn acquiring genital herpes.

As with many other infections, primary infection in the mother poses a greater risk to the newborn than recurrent maternal infection. If the mother has antibody, and this antibody is transmitted through the placenta to the newborn IgG antibody, the chances of infection and disease are lower. If the healthcare provider, the obstetrician in these settings, uses invasive obstetrical procedures, like a fetal scalp electrode, the chances of infection are increased. And, finally, the discordancy of the partner [is a factor].

What that means is that the partner, the male, has genital herpes, has gotten his partner pregnant, has not transmitted genital herpes to the partner at that point in time but carries the risk of transmitting herpes to the pregnant partner during the pregnancy, when she would get a primary case of this infection.