Group B Strep Screening Late in Pregnancy Can Save Newborns

(HealthDay News) -- As women near the end of their pregnancies, they should undergo a rather simple test that can end up saving the life of their newborn.

The test, a swab of the vagina and rectum, is looking for a single offender: a type of bacteria called Group B streptococcus, or GBS.

GBS is relatively common and can be found in about a quarter of pregnant women.

It's also the leading cause of sepsis and meningitis in newborns, according to the U.S. Centers for Disease Control and Prevention. Before prevention methods became widely used, about 8,000 babies would contract the bacteria during birth, with one in 20 dying from the infection. Babies that survive, particularly those who have meningitis, may have long-term problems, such as hearing or vision loss or learning disabilities.

Detection of GBS has improved, thanks to new federal guidelines recommending universal screening of all pregnant women at 35 to 37 weeks of pregnancy.

But doctors still haven't agreed on the best way to treat a mother with a positive GBS reading, particularly regarding the use of antibiotics, said Dr. Craig Rubens, a physician with Children's Hospital and Regional Medical Center in Seattle, and a professor of pediatrics at the University of Washington.

July is International Group B Strep Awareness Month, and doctors are taking the opportunity to urge pregnant women to pay close attention to the GBS test as they near labor.

"I think it's important for women to not only be empowered and ask for the test, but also to understand why they need it," said Janine Cory, a health communicator with the respiratory disease branch of the CDC.

A fetus can contract Group B strep by coming into contact with the bacteria either before or during birth, and signs of illness can occur within hours of birth. GBS is usually found around the vagina and rectum of a pregnant carrier.

During childbirth, the bacteria are transmitted to approximately half of all infants born to carriers, according to the National Institutes of Health, and nearly two of every 1,000 infants in the United States develop invasive infections.

Half of all infants who develop Group B strep meningitis experience long-term neurologic problems, including seizure disorders and mental retardation. About 5 percent of infected infants die, according to the March of Dimes.

The standard practice has been to treat mothers with antibiotics shortly before birth, Cory said. The medications usually are administered as a woman enters labor.

"There is a very regimented way to do the antibiotic," Cory noted. "There's a table for physicians to follow. There's management."

However, the antibiotic needs to be administered at least four hours prior to delivery if doctors want to be sure the bacteria have been killed off, Rubens explained. Some women in labor simply don't have that long.

"Sometimes they're going to deliver more rapidly than we can administer the antibiotic properly," he said. "It's really a logistical problem, because you can't predict how quickly a woman will deliver."

Researchers currently are looking into ways to get around that problem, either by treating a pregnant woman with antibiotics earlier in their term or by giving antibiotics to a newborn child at risk of contracting GBS.

"We need to understand the window of opportunity for delivering antibiotics to either the mother or her baby," Rubens said.

Another treatment possibility under investigation is the development of a GBS vaccine that could be administered to either pregnant women or women of childbearing age.

Rubens said there are a dozen different vaccines in various stages of development, including one that currently is in clinical trials.

"You give the vaccine to the mother, she develops antibodies that clear the bacteria and pass to the baby from the mother," Rubens added. "That way, if the baby is exposed to the bacteria, it has a way to fight back."

Researchers are also looking into ways to speed up screening for Group B strep. The current gold standard involves working up a culture, which can take 24 hours or more.

But many women still are coming into hospitals without having had the test, either because they haven't seen a pediatrician or because they are afraid of it, Cory pointed out.

"Women undergo a battery of tests during pregnancy," Cory said. "Doctors say, 'Oh, we have to poke, pinch, prod.' This is a very easy one, but they need to know that."

Scientists need to come up with a quick and easy test that can confirm the presence of GBS so antibiotic treatment can begin, Rubens stated.

"Rapid testing is still something that needs to be made technically easier," Rubens said. "Some of the newer techniques for rapid testing are not sensitive enough or are too technical. We need better rapid tests that are easier to perform."

On the Web

For more information on Group B strep and newborns, visit the U.S. Centers for Disease Control and Prevention at http://www.cdc.gov/ncidod/dbmd/diseaseinfo/groupbstrep_g.htm.

By Dennis Thompson, HealthDay Reporter
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May 2005