Many Newborns are Protected from Group B Strep, But More Can Be Helped

Group B streptococcus (GBS, also called group B strep) is one of the most common infections in the first week of life. A pregnant woman who has GBS in her birth canal can spread the bacteria to her baby during delivery. A newborn who develops an infection within 7 days of birth, called early-onset GBS, can develop pneumonia, sepsis, or meningitis, illnesses that can be serious and even life-threatening. To prevent these infections, the CDC recommended in 2002 that all pregnant women be tested during their ninth month of pregnancy, between 35 and 37 weeks of gestation. (For more on this, see the section on group B strep in the Pregnancy article.)

For the test, a swab of both the vagina and rectum should be obtained for culture. If GBS are present, the baby can be protected by giving the mother an antibiotic during labor for at least 4 hours before the birth.

In the New England Journal of Medicine article, the CDC published data on how well the "universal screening" guideline was working and summarized what was standing in the way of protecting more babies from group B strep. The researchers said that their analysis showed that the screening recommendations were being followed. More women were being tested and more babies were benefiting from medication given to infected mothers while they were in labor. To spur further improvement, the report noted the types of situations in which the opportunity to use a screening test is missed.

Study Shows More Are Tested, More Get the Needed Treatment
The researchers drew from data on more than 800,000 births in 2003 and 2004. They used data from 10 states and compared it to data from a similar study in 1998 and 1999. They analyzed data for all 254 infants who developed early-onset GBS plus a random sample of 7437 uninfected newborns.

• Screening rates up: The study showed that 85 percent of pregnant women were appropriately screened in the 2002-2003 timeframe. That is a big improvement from 5 years earlier when less than 50% of pregnant women got tested.
• Treatment also up: Treatment rates also improved, the analysis showed. The treatment (an antibiotic) was given to mothers in labor more often than before (31.7 percent of the time in 2003–2004 versus 26.8 percent in 1998–1999). Those whose GBS status called for preventive treatment during labor received the antibiotic 85.1 percent of the time in 2003 and 2004, versus 73.8 percent in 1998 and 1999.

Labor's Unpredictability Thwarts Prevention
The report highlighted "missed opportunities for prevention." Although nearly three-fourths of the infected infants were delivered at term, one of the biggest remaining challenges is preventing GBS infections in infants born early, the researchers observed. Only half of the women delivering early had a GBS screening test before the birth and less than 1 in 5 of those delivering early were tested when they were admitted to the hospital. Of greatest concern, those delivering preterm who were not screened for GBS got antibiotic treatment only 63.4 percent of the time. In addition, the researchers found that women who spent less than 4 hours in the hospital before giving birth were less likely to receive the medication, which is given intravenously.

Improvements could be made in several areas to protect even more newborns, reported the researchers; however, some challenging issues complicate GBS prevention efforts. For example, the researchers noted these difficulties in getting the test done and applying its findings:

• The test needs to be done 35 to 37 weeks into the pregnancy—not earlier because a woman may become colonized later in her pregnancy and not so late that results are not available when the woman goes into labor.
• The test's results need to be available to the labor and delivery team when the woman goes into labor.
• Sometimes, the woman has not undergone screening as she goes into labor and testing cannot be done in time. In the future, rapid tests for GBS could play an important role in these situations, but these tests would need to be as least as sensitive and specific as the culture method.
• Another limitation is the test's failure to detect the presence of GBS. The researchers found that for 61.4 percent of the full-term infants who developed GBS disease, the mother had false-negative culture results.

In Journal Watch Pediatrics and Adolescent Medicine, William P. Kanto, Jr., MD, commented on the progress made and the challenges remaining. The successes of screening for and treating this infection during pregnancy seem "truly remarkable," wrote Kanto. Agreeing with the researchers, Kanto said the focus now should be on closing the gaps, using the test more, and creating systems that ensure appropriate antibiotic treatment for those who need it.

Sources

Babies. Beautiful, Healthy Babies (flyer). 2002. US Centers for Disease Control and Prevention and the National Center for Infectious Diseases. PDF available for download at http://www.cdc.gov/groupbstrep/docs/flyer.pdf through http://www.cdc.gov. Accessed 30 Jun 2009.

Group B Strep Prevention (GBS, baby strep, Group B streptococcal bacteria): FAQ. US Centers for Disease Control and Prevention. Available online at http://www.cdc.gov/groupbstrep/general/gen_public_faq.htm through http://www.cdc.gov. Accessed 30 Jun 2009.

Group B Strep: What You Need to Know (patient handout). US Centers for Disease Control and Prevention. PDF available for download at http://www.cdc.gov/groupbstrep/docs/GBS_Patient_Info.pdf through http://www.cdc.gov. Accessed 30 Jun 2009.

Are You Pregnant: Protect Your Baby from Group B Strep (brochure). 2002. US Centers for Disease Control and Prevention. PDF available for download at http://www.cdc.gov/groupbstrep/docs/gbs_brochure2005-eng.pdf through http://www.cdc.gov. Accessed 30 Jun 2009.

Kanto, WP Jr. 2009 Jun 17. Universal Screening for Group B Strep: Success with Room for Improvement (summary and comment). Journal Watch Pediatrics and Adolescent Medicine. Available online at http://pediatrics.jwatch.org/cgi/content/full/2009/617/1 through http://pediatrics.jwatch.org. Accessed 1 Jul 2009.

March of Dimes. 2007 Oct. Group B Strep Infection (quick reference fact sheet for professionals and researchers). Available online at http://www.marchofdimes.com\[COMPLETE] through http://www.marchofdimes.com. Accessed 30 Jun 2009.

Van Dyke MK et al. 2009 Jun 18. Evaluation of Universal Antenatal Screening for Group B Streptococcus. N Engl J Med 360:2626.

Centers for Disease Control and Prevention, Active Bacterial Core Surveillance, Group B Streptococcus, 2001 and 2003. PDFs available for download at http://www.cdc.gov/ncidod/dbmd/abcs/survreports/gbs01.pdf and http://www.cdc.gov/ncidod/dbmd/abcs/survreports/gbs03.pdf through http://www.cdc.gov. Accessed July 2009.