TUESDAY, Jan. 7, 2003 (HealthDayNews) -- A new study confirms what physicians have known for years: Women with herpes lesions who have Caesarean sections are far less likely to pass the virus on to their babies.
"This is the first true evidence that neonatal herpes is prevented by Caesarean section. Before it was common practice, but it was unproven," says Dr. Zane Brown, lead author of the study, which appears in tomorrow's issue of the Journal of the American Medical Association.
The news was expected. More surprising, though, was the observation that the highest rates of transmission were from women who acquired herpes while they were pregnant, particularly during the final trimester. These women are probably "shedding" the virus, meaning they are contagious without symptoms.
According to the U.S. Centers for Disease Control and Prevention, one in four American women has herpes simplex virus 2 (HSV-2), commonly known as genital herpes. And the ranks are growing, with 1.6 million new cases acquired each year.
Herpes simplex virus 1 (HSV-1) normally occurs around the mouth and lips, but it can be transmitted to the genital area via oral sex. HSV-2 usually occurs only in the genital area.
The virus, which is potentially fatal in newborns, can be transmitted by the mother, usually if she has an active lesion or is shedding at the time of delivery. A C-section will prevent that from occurring.
"The protocol is that you usually perform viral cultures [and] if the viral
cultures are negative, you forget the whole issue," says Dr. Boris Petrikovsky, chairman of obstetrics and gynecology at Nassau University Medical Center in East Meadow, N.Y. "If viral cultures are positive, then everything depends on the gestational age." If the mother is newly pregnant, positive results have little bearing. If the mother is very close to term and the lesion is in the way of the baby, the doctor will perform a C-section.
"If you see any lesions or any recent lesions that you think viral particles are coming off of and can get in touch with the baby, then the clear message is that you should avoid that by doing a C-section," Petrikovsky adds.
The current study looked at 58,362 pregnant women between January 1982 and December 1999.
Consistent with the conventional wisdom, the researchers found that C-sections significantly reduced the transmission rate. They also discovered that transmission occurred less frequently when the mother had overt genital lesions than when she was shedding. This was because lesions alerted the physician to perform a C-section while shedding remained invisible.
The risk for transmission was also higher if the mother had her first episode of herpes during pregnancy.
"The clear message is if you want to prevent women from infecting their babies, you have to prevent them from acquiring herpes in last trimester of pregnancy," Brown says. This means giving all expectant women an HSV blood test and, Brown says, "dragging the partners in kicking and screaming to get a blood test as well." If the woman is negative but her husband or partner is positive, Brown advises abstinence for the duration of the pregnancy or, barring that, antiviral chemotherapy agents for the man until the baby is born.
If the woman tests positive for HSV-2, she should be given the antiviral chemotherapy agents.
At the very least, the study validates current clinical practice.
"For the last 25 years, in contrast to a lot of stuff in medicine, we have been doing the right thing and we need to continue doing Caesarean sections for women who have lesions or symptoms at the time of labor," Brown says.
Some feel the study treads over tired ground, however, and C-sections are overused.
"There's nothing new in the conclusions and the study. We've known all of this for years," Petrikovsky says. "The only thing that changed now -- and it's not in this paper -- is that we realize we're probably doing too many C-sections."
Physicians no longer routinely perform C-sections on women who have a history of herpes, Petrikovsky says, or for women who have positive HSV cultures early in the pregnancy.
An HSV blood test, however, might be able to identify the universe of women for whom a C-section is a reasonable option.
What To Do
For more on herpes and pregnancy, visit the U.S. Centers for Disease Control and Prevention or the American Social Health
Association.
