For more than 30 years, pregnant women with genital herpes routinely have had Caesarean deliveries. But some obstetricians have considered abandoning the practice because they weren't sure it lowered the risk of mother-to-baby transmission.
Now they know it does.
The first major study putting the practice to the test has found that performing C-sections on women with active herpes reduces the rate of newborns becoming infected during delivery.
"We were never reassured that C-sectioning everybody [with active herpes] was the right thing. No data had existed. That's where this study becomes important," said Dr. Iffath Hoskins, executive director of women's services at Memorial Health Medical Center in Savannah, Ga.
Health officials estimate that of the 4 million babies delivered each year, between one in 2,000 and one in 10,000 are infected with either herpes simplex virus-2, more commonly called genital herpes, or herpes simplex virus-1, which originates orally but can infect the genital area. Herpes simplex viruses attack the central nervous system of babies and can have potentially devastating effects, such as cerebral palsy, blindness, deafness and even death.
University of Washington researchers studied 48,390 deliveries at two hospitals that routinely tested women for herpes viruses (although that's not a common practice). They found that a woman's chance of infecting her baby depends greatly on how doctors and nurses manage the delivery. For example, among the 202 women who tested positive for herpes, 60 underwent C-sections because of visible lesions at the time of delivery. None of those mothers infected their infants.
Because treating a newly infected infant with antiviral drugs can be dangerous, the researchers, led by Dr. Zane A. Brown, recommend taking more preventive measures. Those include checking mothers for lesions and performing surgical deliveries. They also advised taking precautions to avoid breaks in the baby's skin, such as limiting invasive fetal monitoring. Scalp electrodes can leave scratches that let the virus get a foothold.
One unexpected finding was that newly infected women who tested negative for herpes were at an even higher risk of transmitting the virus than women who tested positive. That's because newly infected people have the highest concentrations of the virus in their bodies, and because they haven't made antibodies that can protect the fetus.
The researchers said pregnant women should be urged to have a herpes test, have their partners tested and avoid becoming infected through unprotected sex in the final months of pregnancy.
Hoskins said the study affirms the importance of testing every pregnant woman to identify those who "shed the virus unknown to themselves and their providers."
"We'll still miss a few, but we should miss the least amount we can," she said. "This article is reminding us that our current steps are not enough and we should consider the additional personnel and financial expense of getting viral cultures and testing the blood."