Group B Strep Infection

Stages of Pregnancy Slideshow

Medical Author: Steven E. Doerr, MD
Medical Editor: Melissa Conrad Stöppler, MD

• What is group B strep?
• What causes group B strep infection?
• How is group B strep transmitted?
• What are the symptoms of group B strep infection?
• How is group B strep infection diagnosed?
• What is the treatment for group B strep infection?
• Group B Strep At A Glance
• Patient Discussions: Group B Strep - Describe Your Experience

What is group B strep?

Group B strep (GBS) is a bacteria also known as Streptococcus agalactiae. This type of bacteria (not to be confused with group A strep which causes "strep throat") is commonly found in the human body, and it usually does not cause any symptoms. However, in certain cases it can be a dangerous cause of various infections that affect pregnant women and their newborn infants. Group B strep infection can also afflict adults with certain chronic medical conditions.

What causes group B strep infection?

Group B strep can normally be found in 10%-35% of all healthy adult women. It can commonly be found in the intestine, vagina, and/or rectal area. Most women who are carriers of the bacteria (colonized) will not have any symptoms; however, under certain circumstances, both infection of both the mother and/or newborn can develop.

How is group B strep transmitted?

In newborns, GBS infection is acquired through direct contact with the bacteria while in the uterus or during delivery; thus the infection is transmitted from the colonized mother to her newborn. However, not every baby born to a colonized mother will develop GBS infection. Statistics show that about one of every 100-200 babies born to a GBS-colonized mother will develop GBS infection. There are maternal risk factors, however, that increase the chance of transmitting the disease to the newborn:

• labor or membrane rupture before 37 weeks



• membrane rupture more than 18 hours before delivery



• urinary tract infection with GBS during pregnancy



• previous baby with GBS infection



• fever during labor



• positive culture for GBS colonization at 35-37 weeks

Group B strep infection is not a sexually transmitted disease (STD).

Group B Strep - Describe Your Experience

The MedicineNet physician editors ask:

Please describe your experience with group B strep.

Comment submissions for this question have ended.
See 21 Viewer Comments

View Comments

Suggested Reading by Our Doctors

• cefdinir, Omnicef - Explains the medication cefdinir (Omnicef), a drug used to treat infections such as middle ear, tonsillitis, strep throat, bronchitis, pneumonia, and skin and soft tissue.
• Pregnancy: Third Trimester Tests During Pregnancy - Learn about tests performed during the third trimester of pregnancy. These tests include group B strep screening, nonstress test, contraction stress test, electronic fetal heart monitoring, and a biophysical profile.
• Strep Throat - Learn about strep throat symptoms like fever, nasal drainage, sore throat, swollen glands, difficulty swallowing, irritability. Causes and treatments are discussed in the information.

Read more Group B Strep related articles »

Latest Medical News

• Strep B Seems to Trick Immune System
• Group B Strep Screening Guidelines Sparing Newborns