Managing Group B Strep during Pregnancy
“You’ve tested positive for group B strep,” said the voice over the phone. I considered my first pregnancy to be mostly free of the usual problems and complaints that plague other moms-to-be. Having passed all of the routine pregnancy tests with flying colors, nothing prepared me for testing positive for group B strep.
I was floored, totally unaware of what this diagnosis was, or how it could affect my unborn child and myself.
What is Group B Strep?
Group B streptococcus (GBS) is a natural bacterium found in the vagina, bowel, bladder, rectum, and throat. According to the National Organization for Rare Disorders (NORD), the streptococcus bacteria reproduce and colonize in the mucous membranes of these body parts. GBS can be transmitted through touch, air, or sexual contact. About one in four pregnant women are considered carriers of GBS but may show little or no symptoms.
Are You at Risk?
Group B strep can be detected during pregnancy through a routine swab of the vagina and/or rectum for a culture test. According to the Centers for Disease Control and Prevention (CDC), in Atlanta, Georgia, this test should be done when a woman is between 35 to 37 weeks pregnant.
When a culture test is positive, the result is that the pregnant woman is a carrier for GBS—not that she or her baby will become ill. The CDC states that pregnant women who are considered high risk for having a baby with GBS have had one or more of the following:
- Previous baby with GBS disease
- Urinary tract infection due to GBS
- GBS carriage late in pregnancy
- Fever during labor
- Rupture of membranes (“water breaks”) 18 hours or more before delivery
- Labor or rupture of membranes before 37 weeks
“If you have vaginitis, cervicitis, or other infections, your risk goes up,” says Dr. Tessie Tharakan, MD, a maternal-fetal medicine specialist at Columbia Presbyterian Hospital in Manhattan. In some pregnant women, GBS infection may cause urinary tract infections, endometritis, womb infections, stillbirths, and/or premature delivery if undiagnosed.
Additionally, a study published in the December 2005 issue of Obstetrics & Gynecology and conducted by Dr. Renee D. Stapleton of the University of Washington School of Medicine in Seattle, states that, “African-American women, healthcare workers, and overweight women are at increased risk for carrying group B streptococcus (GBS) during pregnancy.”
What Happens during Labor and Delivery?
Carriage of GBS becomes important during labor and delivery when a woman is administered a course of IV antibiotics such as penicillin or ampicillin (clindamycin or erythromycin are usually substituted for women allergic to penicillin) every four hours.
Pregnant women who have been diagnosed as GBS-positive carriers should not be given oral antibiotics before labor because any treatment at this time will not prevent their babies from possible exposure to this infection. According to the guidelines published in August 2003 by the CDC, the only exception to this rule is when GBS is, “identified in urine during pregnancy.” Group B strep found in the urine of expectant mothers should be treated at the time of discovery.
What if You Labor before Being Tested?
There is an inherent risk involved in the testing time frame. It has been widely researched and reported that cultures collected before week 35 to week 37 don’t accurately predict whether a woman will have GBS at the time of delivery.
What if a woman goes into labor before the 35th week of pregnancy and hasn’t been tested for GBS? If this should happen, both the American College of Obstetricians and Gynecologists (ACOG) and the CDC recommend that the mom-to-be is administered IV antibiotics at the time of labor.
“Premature babies are at a higher risk, so preterm labor is usually treated with antibiotics,” explains Dr. Tharakan. When the laboring woman’s contractions are stopped and a premature delivery is avoided, the antibiotic treatment is halted.
One out of every 100 to 200 babies born to women who carry GBS develop signs and symptoms of the infection. Generally, babies are exposed to the GBS bacterium during labor and delivery; however, there are several other ways that they can come in contact with it—when the mother’s water breaks, when the bacteria travel up from the mother’s vagina into the uterus, or swallowing/inhaling the bacteria while passing through the birth canal.
Those newborn babies who become infected with GBS are classified as having one of two stages—early or late-onset. Infants infected with the bacterium either at birth or by their seventh day of life are diagnosed with early-onset GBS, which can lead to inflammation of the baby’s lungs, spinal cord, or brain; meningitis; or sepsis. It is also a frequent cause of newborn pneumonia.
Infants who appear to be born healthy but develop symptoms of GBS from one week to several months after birth are diagnosed with late-onset GBS. This is a rare condition, since only about half of late-onset GBS disease comes from a mother who is a GBS carrier. The source of infection for the other cases of late-onset GBS is unknown.
According to Dr. Carol J. Baker, MD, professor of pediatrics, Molecular Virology & Immunology at the Baylor College of Medicine in Houston, Texas, these babies can pick up GBS from a variety of different sources. “This is another possibility within the ‘community spread’ syndrome. Both mom and baby come home from the hospital together, and the mother may transmit it to her baby through poor hygiene (not washing hands), or dad might have it and transmit it to the baby through contact. Or the baby could have come in contact with it through the hospital environment.”
Meningitis and pneumonia are considered symptoms of late-onset infection, which can bring long-term problems associated with the infant’s nerve system; however, Dr. Tharakan believes that, “if infection in babies is promptly treated, there is usually no long-term damage.”
The medical community is working to create a vaccination that protects women and their babies from the dangers of group B strep. Dr. Baker, who with her colleagues has been testing a conjugate vaccination in trials, has seen some positive results. But until a vaccination becomes available to the public, it cannot be stressed enough to get tested for this bacteria during the 35th to 37th week of pregnancy. If your doctor doesn’t mention it, bring it up during your routine visits. Knowing your culture result before you go into labor can help save your baby’s life.
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