No lesion at delivery
If a woman doesn't have herpes lesions at the time of delivery, the standard of care recommended by the American College of Obstetrics and Gynecology (ACOG) is vaginal delivery. This does expose the baby to a very small risk of infection from possible asymptomatic shedding. The case for vaginal delivery is built on a number of strong arguments.
First, the percentage of babies who acquire neonatal herpes from mothers who have no active lesions at delivery is exceedingly small. In a study of 15,923 pregnant women in Seattle, only one baby contracted neonatal herpes from a mother with recurrent HSV who was shedding asymptomatically at delivery (Brown, New England Journal of Medicine, 1991). Other studies have found an even lower rate of transmission.
"The risk is not zero, but it's extremely low," says Stanberry. By comparison, studies have found that many more women shed virus at delivery -- approximately 1.4% of women tested by viral culture, and some 20% of women tested by ultra-sensitive PCR (polymerase chain reaction) technology. The dramatic difference between the numbers of babies infected and mothers shedding virus have led researchers to conclude that even babies who are exposed to viral shedding rarely become infected, probably because of maternal antibodies passed through the placenta.
The second argument for vaginal delivery is that there is no practical way to detect viral shedding quickly enough to affect a delivery decision. Prior to 1988, ACOG recommended that doctors culture women for HSV-2 in the last few weeks before delivery, in an effort to identify women who are shedding. However, several studies demonstrated that these culture tests are useless for predicting which women will be shedding at delivery, as shedding tends to last only a few days at most.
While some doctors still continue the practice of weekly cultures to determine the need for a C-section, experts now believe this simply causes unnecessary cesareans - without providing any protection to babies.
For example, a 1995 study at University of Texas Southwestern Medical Center in Dallas showed that since the hospital adopted ACOG's 1988 recommendation of delivering women with genital herpes vaginally, in the absence of visible lesions, the rate of cesarean delivery dropped by 37%, and no babies had contracted neonatal herpes (Roberts et al., Obstetrics &' Gynecology, 1995).
Some mothers do request a C-section because they want to do everything possible to avoid infecting their babies. "Many mothers may be willing to put themselves at risk for their babies," says Laurie Scott, M.D., of the Department of Obstetrics and Gynecology at the University of Texas. "But the reality is that a C-section is a potentially dangerous situation."
Maternal illness following a cesarean is approximately 28%, compared with 1.6% following a vaginal delivery. Cesareans require long recovery times, and in some instances can even be fatal. "If we were doing C-sections on every mother with genital herpes, we'd end up losing almost as many women as we were saving babies," says Zane Brown.
Furthermore, the protection offered by C-sections is not absolute. In various studies, between 16% and 30% of infants infected with neonatal herpes were born by cesarean (in most of these cases the cesarean was performed after the membranes had ruptured).
At the same time, babies delivered vaginally, even in the presence of active lesions have an infection rate of only 0.25%-5%."Every center that does research has cases where a lesion is identified after delivery," explains Brown. "The obstetrician will notice it while stitching the mother after an episiotomy, for example. In most cases, those babies don't get infected". This again shows the protective power of maternal antibodies.
In short, for mothers with recurrent genital herpes, even the practice of delivering by cesarean in the case of visible lesions is conservative in light of the very few actual cases of neonatal herpes.
"We're not operating on mathematical assumptions," says Scott. "We're operating on real-world observations of how few babies get neonatal herpes."
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