Group B streptococcal (GBS) infection is an infection with a bacteria.


Newborn babies can get the bacteria:

  • Before birth, the fetus may breath in fluid around it
  • During delivery, from the birth canal
  • After birth, by touch, often with the mother

Vaginal Bacteria Spreading to Fetus

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Risk Factors

Black newborns are at increased risk. It is also common in mothers who give birth at a young age.

Things that may raise your baby's risk are:

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


A pregnant woman usually doesn’t have symptoms.

The newborn may have

  • Fever
  • Breathing problems
  • Not eating well
  • Crying a lot
  • Problems waking


GBS colonization may be found during an office visit. Testing should be done about one month before the baby is due.

Your baby may have:

  • Blood tests
  • Urine tests
  • Spinal fluid test


For the Mother

If you have GBS or are at high risk, your doctor will give you antibiotics. This will lower the risk that your baby will get sick. It must be given at least four hours before birth. Some babies can still get GBS.

If GBS is found in the urine, women should be treated for this infection with antibiotics.

For the Baby

A newborn who may have GBS may be need a couple of extra days of medical care. Blood and urine tests may be done. Antibiotics will be given.


Follow these steps:

  • Get screened for GBS at 35-37 weeks.
  • Talk to your doctor about taking antibiotics during birth if you have not been tested but are at risk.

The American Congress of Obstetricians and Gynecologists

Group B Strep Association


The Society of Obstetricians and Gynaecologists of Canada

Women's Health Matters


De Tejada BM, Pfister RE, Renzi G, et al. Intrapartum Group B streptococcus detection by rapid polymerase chain reaction assay for the prevention of neonatal sepsis. Clin Microbiol Infect. 2011;17(12):1786-1791.

Group B strep (GBS). Centers for Disease Control and Prevention website. Available at: Updated May 29, 2018. Accessed July 23, 2018.

Group B strep infection: GBS. American Pregnancy Association website. Available at: Updated March 2, 2017. Accessed July 23, 2018.

Group B streptococcal infection in infants less than 3 months old. EBSCO DynaMed Plus website. Available at: Updated February 1, 2017. Accessed July 23, 2018.

Ohlsson A, Shah VS. Intrapartum antibiotics for known maternal Group B streptococcal colonization. Cochrane Database Syst Rev. 2009;(3):CD007467.

Puopolo KM, Madoff LC, Eichenwald EC. Early-onset Group B streptococcal disease in the era of maternal screening. Pediatrics. 2005;115(5):1240-1246.

Woodgate P, Flenady V, Steer P. Intramuscular penicillin for the prevention of early onset Group B streptococcal infection in newborn infants. Cochrane Database Syst Rev. 2004;(3):CD003667.

Last reviewed May 2018 by EBSCO Medical Review Board Kathleen A. Barry, MD  Last Updated: 7/24/2018