What Is Group B Strep?
Group B strep (GBS) is a type of bacteria that is naturally found in the digestive tract and birth canal in up to 1 in 4 pregnant women who “carry” or are “colonized” with GBS. Since levels of GBS can change, each pregnancy can be different. Carrying GBS does not mean that you are unclean. Anyone can carry GBS.
Unfortunately, babies can be infected by GBS before birth and up to about 6 months of age due to their underdeveloped immune systems. Only a few babies who are exposed to GBS become infected, but GBS can cause babies to be miscarried, stillborn, or become very sick and sometimes even die after birth. GBS most commonly causes infection in the blood (sepsis), the fluid and lining of the brain (meningitis), and lungs (pneumonia). Some GBS survivors have permanent handicaps such as blindness, deafness, mental challenges, and/or cerebral palsy.
Fortunately, more than 90% of GBS infections that develop at birth can be prevented if women who have tested positive receive at least 4 hours of IV antibiotics just prior to delivery.
HOW DO I KNOW IF I CARRY GBS?
Most women do not have any symptoms, but GBS can cause symptoms such as vaginal burning/irritation and/or unusual discharge which may be mistaken for a yeast infection and treated incorrectly.1 If you have “vaginitis” symptoms, see your care provider promptly for an exam and possible GBS testing. Be aware that bacteria can be passed between sexual partners.
GBS can also cause bladder infections, with or without symptoms. Your provider should do a urine culture for GBS and other bacteria (this is not the standard prenatal urine “dipstick” check) at the first prenatal visit. GBS in your urine means that you may be heavily colonized which puts your baby at greater risk.2 If your urine tests positive, your provider should consider you as “GBS colonized” for this pregnancy so that you receive IV antibiotics for GBS when labor starts/your water breaks. If you have a significant level of GBS in your urine, your provider should also prescribe oral antibiotics at time of diagnosis. GBSI advocates a recheck (“test of cure”) one month after treatment.
It is now the standard of care in the USA and several other countries for all pregnant women to be routinely tested for GBS at 35–37 weeks of each pregnancy (unless already positive in their urine in current pregnancy.) Your provider will perform a swab test of your vagina and rectum and obtain the test results in 2–3 days. If the test result is positive, you carry GBS.
A few hospitals will offer rapid, DNA-based tests which can be performed during labor or any time during pregnancy with results in less than 2 hours.2 Because your GBS status can change by the time you go into labor, culture tests can show a false negative, or your culture test results may not be available, these rapid tests can help supplement your routine GBS testing.
HOW CAN GBS INFECT MY BABY?
GBS can infect your baby even before your water breaks. GBS infections before birth are called “prenatal-onset.”
GBS can cause preterm labor, causing your baby to be born too early.
GBS infection can also cause your water to break prematurely without labor starting, causing your baby to lose a significant layer of protection.
It is thought that babies are most often infected with GBS as they pass through the birth canal. GBS infections within the first week of life are called “early-onset.”
Babies can become infected with GBS by sources other than the mother. GBS infections after the first week of life are called “late-onset.”
Be aware that your womb and/or C-section wound can become infected by GBS.
HOW CAN I HELP PROTECT MY BABY
Ask to have a urine culture for GBS and other bacteria done at your first prenatal visit.3 If you have a significant level of GBS in your urine, request a recheck one month after being treated.
See your provider promptly for any symptoms of vaginal infection.4 (In the future, vaginal pH testing may be recommended to detect abnormal vaginal flora.5)
GET TESTED at 35–37 weeks. If the test result is positive, you should receive IV antibiotics when labor starts or your water breaks.
Get a copy of all culture test results and keep them with you!
Plan ahead if you have short labors or live far from the hospital. Ask about a late third-trimester penicillin shot as a possible safeguard.6 (Note: not a widely accepted strategy.) The IV antibiotics you receive in labor generally take 4 hours to be effective.
Tell your provider if you are allergic to penicillin. There are IV antibiotic alternatives.7
Know that “alternative medicine” treatments such as garlic or tea tree oil have not been proven to prevent your baby from becoming infected.8 Some are unsafe.
Avoid unnecessary, frequent, or forceful internal exams. Knowing how far you are dilated does not accurately predict when your baby will be born and may push GBS closer to your baby.8 Vaginal or perineal ultrasounds are a less invasive option.9
Discuss the benefits vs. risks of possible methods of induction with your provider early in pregnancy as not all providers ask before “stripping” (also known as “sweeping”) membranes.
Ask your provider to not strip your membranes if you test positive for GBS. (Be aware that you may test negative, but be GBS positive later.) GBS can cross even intact membranes and procedures such as stripping membranes and using cervical ripening gel to induce labor may push bacteria closer to your baby.10-12
If you are having a planned C-section, talk to your provider about the risks vs. benefits of starting IV antibiotics well before your incision. C-sections may not completely prevent GBS infection although the risk during a planned C-section is extremely low if performed before your labor starts/water breaks.
Talk to your provider about whether or not to use internal fetal monitors and/or have your water broken before you have had IV antibiotics for at least 4 hours.
…when my water breaks or I start labor?
Call your care provider. Remind him/her of your GBS status. If you have already had a baby with GBS disease or have had GBS in your urine in this pregnancy, you should receive IV antibiotics regardless of this pregnancy’s GBS test results. Report any fever.
Go to the hospital immediately if you should receive IV antibiotics. Have all test results with you. Tell the nurses that you need to start IV antibiotics for GBS.
If you do not have a GBS test result, and your hospital does not offer a rapid GBS test, per the CDC guidelines you should be offered IV antibiotics based on the following risk factors:
Your baby will be born before 37 weeks.
Your water has been broken 18+ hours without delivering. (Even 12+ hours increases the risk.11)
You have a fever of 100.4 °F or higher during labor
In half of GBS infections, the mother has no risk factors.12 This is why testing is so important!
…after my baby is born?
If you give birth before you have had 4 hours of antibiotics, the hospital may culture your baby and should observe him/her for 48 hours.2 You can ask about your baby having antibiotics while waiting for the results of the culture. (Note: Recent research suggests antibiotic treatment may disturb the baby’s protective intestinal flora.)
Have everyone wash their hands before handling your baby.
Breastfeeding can supply your baby with important antibodies to fight infection.15 Although possible GBS transmission from breast milk has been suggested 16, overall the benefits of breastfeeding far outweigh any potential risk of exposure to GBS.17,18
Make sure everyone who takes care of your baby knows the symptoms of GBS infection in babies and how to respond.
WHAT GBS SYMPTOMS DO BABIES SHOW?
Contact your care provider immediately if you notice:
Decreased or no fetal movement after your 20th week
You have any unexplained fever
Take your baby to the emergency room or call your baby’s doctor immediately if you notice these signs:
High-pitched cry, shrill moaning, whimpering
Marked irritability, inconsolable crying
Constant grunting as if constipated
Feeds poorly or refuses to eat, not waking for feedings
Sleeping too much, difficulty being aroused
High or low or unstable temperature; hands and feet may still feel cold even with a fever
Blotchy, red, or tender skin
Blue, gray, or pale skin due to lack of oxygen
Fast, slow, or difficult breathing
Body stiffening, uncontrollable jerking
Listless, floppy, or not moving an arm or leg
Tense or bulgy spot on top of head
Infection (pus/red skin) at base of umbilical cord or in puncture on head from internal fetal monitor
1. Maniatis AN, Palermos J, Kantzanou M, Maniatis NA, Christodoulou C, Legakis NJ. Streptococcus agalactiae: a vaginal pathogen? Department of Microbiology, Medical School, University of Athens, Greece. J Med Microbiol.;44(3):199-202, March 1996.
2. Morbidity and Mortality Weekly Report, Prevention of Perinatal Group B Streptococcal Disease, Revised Guidelines from CDC, 2010, Vol. 59, No. RR-10, pages 7, 22. November 19, 2010.
3. US. Preventive Services Task Force, Screening for Asymptomatic Bacteriuria in Adults, Reaffirmation Recommendation Statement, July 2008.
4. McGregor, James A., “Infection and prematurity: the evidence is in,” Medical Tribune Opinion, Feb. 6, 1997.
5. Saling E, J Lüthje J, Schreiber MD Institute for Perinatal Medicine, Berlin, Germany (Translation into English: Amos Grunebaum MD FACOG, Cornell University, New York). Self-Care-Program for Pregnant Women.
6. Pinette MG, Thayer K, Wax JR, Blackstone J, Cartin A. “Efficacy of intramuscular penicillin in the eradication of group B streptococcal colonization at delivery.“ J Matern Fetal Neonatal Med. 2005 May; 17(5):333-5.
10. McGregor JA, Parsons A, French JI, “Ultrasound Illustration of the Functional Connectedness of the Lower and Upper Reproductive Tracts”
11-2. SOGC Clinical Practice Guidelines. The Prevention of Early-onset Neonatal Group B Streptococcal Disease. No. 149, September 2004.
12-1. DeMott K., “Cervical Manipulations linked to Perinatal Sepsis: Consider GBS-specific Chemoprophylaxis (Eight Case Reports),” OB/GYN News, Oct. 15, 2001.
12-2. Rosenstein N, Schuchat A. Neonatal GBS Disease Study Group. “Opportunities for prevention of perinatal group B streptococcal disease: A multistate surveillance analysis.” Obstet Gynecol 90:901-6. 1997.
15. Lagergard T, Thiringer K, Wassen L, Schneerson R, Trollfors B. Department of Medical Microbiology, University of Goteborg, Sweden. “Isotype composition of antibodies to streptococcus group B type III polysaccharide and to tetanus toxoid in maternal, cord blood sera and in breast milk.” Eur J Pediatr. 151(2):98-102. Feb 1992.
16. Lanari M, Serra L, Cavrini F, Liguori G, Sambri V , “Late-onset group B streptococcal disease by infected mother’s milk detected by polymerase chain reaction.” New Microbiol. 2007 Jul;30(3):253-4.
17. Sarasa NL, “Mother’s Milk Still Best-and We Must Do Better.” MEDICC Rev. 2013 Jan;15(1):48.
18. American Academy of Pediatrics Policy Statement, “Breastfeeding and the Use of Human Milk”, Pediatrics Vol. 129 No. 3 March 1, 2012, pp e827-e841 (doi: 10.1542/peds.2011-3552)