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Health Information Center

Group B Streptococcal Infection

  • Cynthia M. Johnson, MA
Publication Type:


Group B Streptococcal Infection



Group B streptococcal (GBS) infection is a rare illness in newborns. It is caused by a bacteria that is often passed to the baby in the birth canal.


GBS is a specific bacteria. It is common to find this bacteria on the skin along with other bacteria. GBS may pass to newborns in the birth canal during delivery. They may also pick up the bacteria after birth when they come in contact with someone who has the bacteria on their skin.

Bacteria Spreading to Fetus.

DW00030_96472_1http://services.epnet.com/getimage.aspx?imageiid=61706170DW00030_96472_1.jpegBirthing Complications - Intrauterine (Uterine) InfectionNULLjpegDW00030_96472_1NULL\\hgfiler01a\intellect\images\DW00030_96472_1.jpegNULL101NULL2006-01-103234006170_28211Copyright © Nucleus Medical Media, Inc.

Risk Factors

Things that may raise a baby's risk of GBS infection include:

  • An infected mother who does not get treated before birth
  • The mother had a prior baby with GBS infection
  • The mother had a urinary tract infection due to GBS
  • Labor or water breaking before 37 weeks
  • Water breaking for 18 hours or more before birth
  • Mother had a fever during labor
  • Frequent pelvic exams during labor
  • Use of tools to check the fetus


The newborn with GBS infection may have:

  • Fever
  • Breathing problems
  • Problems feeding
  • Long periods of crying
  • Problems waking

A pregnant woman will rarely have symptoms.


All pregnant women are tested for GBS about 5 weeks before delivery. A cotton swab will be swiped over the vagina and rectum. A lab will test the sample for GBS.

A baby born to a mother with GBS will not always be ill. Tests to confirm GBS infection in the baby may include:

  • Blood tests
  • Urine tests
  • Lumbar puncture—to collect fluid around the spine



The risk of a GBS infection in newborns may be lowered by getting proper prenatal care.

For the Mother

A mother can have GBS and not be sick. Treatment may be done to lower the risk of passing GBS to the baby. Antibiotics will be given through an IV during labor. Treatment must be given at least four hours before birth.





  • Group B strep (GBS). Centers for Disease Control and Prevention website. Available at: http://www.cdc.gov/groupbstrep/index.html.
  • Group B strep infection: GBS. American Pregnancy Association website. Available at: http://americanpregnancy.org/pregnancy-complications/group-b-strep-infection.
  • Group B streptococcal infection in infants less than 3 months old. EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/group-b-streptococcal-infection-in-infants-less-than-3-months-old.
Last Updated:

This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.