Group B Streptococcus Infection During Pregnancy

Group B streptococcus (GBS) is a type of bacteria often found in healthy women. GBS usually does not cause any symptoms or harm to healthy adult women, but the bacteria can make a baby very sick if it is passed to the baby during childbirth. GBS is not a sexually transmitted disease (STD). GBS is different from Group A streptococcus, the bacteria that causes "strep throat."


GBS bacteria can be found in the intestinal, reproductive, and urinary tracts of women. It can also be found in the female genital tract, most often in the vagina and rectal areas.


In pregnancy, GBS can be in the following places:

  • Genital tract without symptoms.

  • Rectum without symptoms.

  • Urine with or without symptoms (asymptomatic bacteriuria).

  • Urinary symptoms can include pain, frequency, urgency, and blood with urination (cystitis).

Pregnant women who are infected with GBS are at increased risk of:

  • Early (premature) labor and delivery.

  • Prolonged rupture of the membranes.

  • Infection in the following places:

  • Bladder.

  • Kidneys (pyelonephritis).

  • Bag of waters or placenta (chorioamnionitis).

  • Uterus (endometritis) after delivery.

Newborns who are infected with GBS can develop:

  • Lung infection (pneumonia).

  • Blood infection (septicemia).

  • Infection of the lining of the brain and spinal cord (meningitis).


Diagnosis of GBS infection is made by screening tests done when you are 35 to 37 weeks pregnant. The test (culture) is an easy swab of the vagina and rectum. A sample of your urine might also be checked for the bacteria. Talk with your caregiver about a plan for labor if your test shows that you carry the GBS bacteria.


If results of the culture are positive, showing that GBS is present, you likely will receive treatment with antibiotic medicines during labor. This will help prevent GBS from being passed to your baby. The antibiotics work only if they are given during labor. If treatment is given earlier in pregnancy, the bacteria may regrow and be present during labor. Tell your caregiver if you are allergic to penicillin or other antibiotics. Antibiotics are also given if:

  • Infection of the membranes (amnionitis) is suspected.

  • Labor begins or there is rupture of the membranes before 37 weeks of pregnancy and there is a high risk of delivering the baby.

  • The mother has a past history of giving birth to an infant with GBS infection.

  • The culture status is unknown (culture not performed or result not available) and there is:

  • Fever during labor.

  • Preterm labor (less than 37 weeks of pregnancy).

  • Prolonged rupture of membranes (18 hours or more).

Treatment of the mother during labor is not recommended when:

  • A planned cesarean delivery is done and there is no labor or ruptured membranes. This is true even if the mother tested positive for GBS.

  • There is a negative culture for GBS screening during the pregnancy, regardless of the risk factors during labor.

The infant will receive antibiotics if the infant tested positive for GBS or has signs and symptoms that suggest GBS infection is present. It is not recommended to routinely give antibiotics to infants whose mothers received antibiotic treatment during labor.


  • Take all antibiotics as prescribed by your caregiver.

  • Only take medicine as directed by your caregiver.

  • Continue with prenatal visits and care.

  • Return for follow-up appointments and cultures.

  • Follow your caregiver's instructions.


  • You have pain with urination.

  • You have frequent urination.

  • You have blood in your urine.


  • You have a fever.

  • You have pain in the back, side, or uterus.

  • You have chills.

  • You have abdominal swelling (distension) or pain.

  • You have labor pains (contractions) every 10 minutes or more often.

  • You are leaking fluid or bleeding from your vagina.

  • You have pelvic pressure that feels like your baby is pushing down.

  • You have a low, dull backache.

  • You have cramps that feel like your period.

  • You have abdominal cramps with or without diarrhea.

  • You have repeated vomiting and diarrhea.

  • You have trouble breathing.

  • You develop confusion.

  • You have stiffness of your body or neck.


  • Understand these instructions.

  • Will watch your condition.

  • Will get help right away if you are not doing well or get worse.