GBS (group B streptococcus)

Group B streptococcus is a bacteria that about 10-30% of pregnant women have.  It is not a sexually transmitted disease.  A woman with GBS can give it to her baby during a vaginal delivery. Women do not have symptoms if they have GBS and do not usually need to be treated.

  • About one or two babies out of 100 whose mothers have GBS can become infected.
  • the infection can develop early or late
    • early infections develop within the first 7 days.
    • late infections develop after 7 days
  • infections cause inflammation of the baby’s blood, lungs, brain or spinal cord.
  • infections can cause death in about 5% of infected babies.

To test for GBS a swab like a Q-tip is placed in the vagina and rectum to obtain a sample.  It is sent to a lab to grow in a culture.  The results come back to our office within 7 days.

Cultures are most useful between 35 and 37 weeks of pregnancy.  If the test is positive, you can be treated during labor.  Babies whose mothers are positive and do not get treated are 20 times more likely to get infected than those whose mothers receive treatment.

Penicillin is the most common antibiotic used to treat GBS. It is given in your I.V. during labor.  Be sure to tell the hospital staff if you are GBS positive (it is also written on your chart that is sent from the office to labor and delivery).  If you are allergic to Penicillin, there are other antibiotics that we can use.

Women who have cesarean births do not need antibiotics for GBS treatment since the baby does not pass through the birth canal. Your doctor may give you antibiotics for another reason.