Pregnancy Health Center
baby graphicLabor and Delivery

Group-B Streptococcus

Group B streptococcus (GBS) is a type of bacteria that may be carried by pregnant women. If passed to the newborn during the birth process, it can cause serious illness in the newborn.

GBS bacteria live in the intestinal tract and are usually harmless. Between 10% and 30% of pregnant women carry GBS in their birth canal or rectum. Although 99% of infants who come in contact with GBS during the birth process do not become ill, those who do can develop severe, life-threatening complications. Fortunately, treatment is available.

GBS itself is not a disease, but it can cause serious illnesses including sepsis (blood infection), pneumonia, and meningitis. Most infants infected with GBS develop symptoms in their first week of life, but symptoms sometimes appear when the infant is 1 week to 3 months old.

Fifteen to 30% of babies who survive meningitis triggered by GBS may have long-term health problems such as hearing and vision loss, learning disabilities, cerebral palsy, and seizure disorders.

How Do I Know I Have It?

When you are 35- to 37-weeks pregnant, your doctor may take a culture by swabbing the outer part of the vagina and rectum and have it tested for GBS as part of the routine workup. (Carriers of GBS usually have no symptoms.) Results are available in a few days.

Some doctors do not test for GBS; instead, they will treat any woman who has a risk factor associated with GBS infection in newborns, including:

How Can I Treat It?

If a test indicates you carry GBS, your doctor will give you intravenous antibiotics during your labor and delivery. This treatment prevents about 78% of GBS infections in newborns.

If you are not tested for GBS but are considered high-risk, your doctor will give you the same antibiotic treatment.

How Can I Prevent?

There is no foolproof way to avoid contracting GBS. While antibiotics can treat GBS infection, the bacteria are very widespread and carriers often have no symptoms. If you have any of the risk factors that increase your chances of having a GBS-infected baby, be sure to discuss treatment options with your doctor.

The National Institutes of Health (NIH) has reported positive results from an experimental GBS vaccine that, when approved, may protect mothers and their newborns in the future.

Frequently Asked Questions

Q: I got strep throat during my pregnancy. Does that mean I have GBS?

A: Strep throat is commonly caused by Group A streptococcus, not Group B. You still may be a GBS carrier, though GBS most likely did not cause your strep throat.

Q: If my test shows I carry GBS, will I be a carrier my whole life?

A: Usually not. GBS tends to come and go.

Review Date: June 29, 2001
Reviewed By: Peter Chen, M.D., Obstetrics and Gynecology, University of Pennsylvania School of Medicine. Review provided by VeriMed Healthcare Network.


The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed physician should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. Copyright 2001 A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.

adam.com