Group B Strep Screening: Don’t Wait Until It’s Too Late
Group B streptococcus (GBS) can cause serious illness or death in a newborn. You might not have heard of this disease. But if you are pregnant or thinking of getting pregnant, find out how a simple screening test and antibiotic treatment can protect you and your baby.
What Is GBS?
Group B strep is a bacterium that normally lives in the intestinal and urinary tracts and is commonly found in vaginal and/or rectal areas. GBS can sometimes cause illness in newborn babies, pregnant women, elderly adults, and adults with chronic medical conditions (eg, diabetes, liver disease, cancer).
This infection is generally easy to treat in adults. But, for newborn babies, it can lead to life-threatening infections, such as sepsis
(blood infection) and meningitis (infection of the fluid and lining surrounding the brain). In very rare instances, babies who have had meningitis can develop long-term problems, such as hearing and/or vision loss or learning disabilities, and they can even die if the infection is left untreated.
Newborn babies become infected with GBS in three ways:
- Before birth—Bacteria in the vagina can spread up the birth canal into the uterus and infect the amniotic fluid surrounding the baby. The baby becomes infected by inhaling the infected fluid into the lungs.
- During birth—The baby can come in contact with the bacteria in the birth canal.
- After birth—The baby can come in contact with the bacteria through intimate physical contact with the mother.
Fortunately, not all babies who are exposed to the bacteria will become infected.
How Do I Know If I’m at Risk?
GBS is present in about 25% of all healthy adult women. Not all women with the bacteria will pass it on. The following factors suggest that steps need to be taken to reduce the risk of passing the GBS bacteria to the baby:
- A previous baby with GBS
- GBS bacteria present in urine during any trimester of the current pregnancy
- Positive GBS screening culture in third trimester of current pregnancy
Unknown GBS status and:
- Labor or rupture of the membranes (water breaking) before 37 weeks gestation
- A rupture of the membranes 18 hours or more before delivery
- A fever during labor
What Are the Symptoms of GBS?
Usually, the pregnant woman has no symptoms of GBS. In pregnant women, GBS infections can cause infection of the uterine lining or amniotic fluid and can lead to a miscarriage
. Two forms of infection occur in newborns.
This produces illness soon after birth, usually within the first 24-48 hours. Problems can include
usually occurs one week to three months after birth. Medical problems associated with late-onset disease may include sepsis and meningitis. There is a chance that infants with meningitis will have long-term problems, such as
, hearing loss, and developmental problems.
Newborns with GBS diseases can die if they do not receive treatment.
Symptoms for both early and late onset include:
- Trouble breathing
- Vomiting and diarrhea
- Temperature instability (high and low)
- Poor feeding
If you notice any of these symptoms in your baby (especially if you have tested positive for GBS), call the doctor right away.
Screening for GBS bacteria is simple. Your doctor will take a swab of the of the vagina and rectum about one month before the baby is due and will send this sample to a lab to test for the presence of the bacteria. Test results are usually available in 24–48 hours.
What to Expect If Your Test Comes Back Positive
The most common treatment is to give IV antibiotics (given through a vein in the arm or hand) during labor
. If your baby is diagnosed with GBS, he will be treated with IV antibiotics.
Using What You Know
The first thing you can do is make sure your doctor screens you for GBS before your delivery date at 35-37 weeks. If you have been identified as a GBS carrier, make sure to tell your doctor of your status when your water breaks or you arrive at the hospital in labor.
By getting screened and treated during labor (if you have GBS), you can reduce the risk of your child developing GBS.
American Academy of Family Physicians
American Congress of Obstetricians and Gynecologists
The Canadian Women's Health Network
The Society of Obstetricians and Gynaecologists of Canada
Group B strep infection: GBS. American Pregnancy Association website. Available at: http://www.americanpregnancy.org/pregnancycomplications/groupbstrepinfection.html. Updated March 2011. Accessed September 13, 2012.
Group B streptococcal infection in infants less than 3 months old. EBSCO DynaMed website. Available at: http://www.ebscohost.com/dynamed/. Updated September 11, 2012. Accessed September 13, 2012.
Group B streptococcus and pregnancy.
American Congress of Obstetrics and Gynecology website. Available at:
Accessed September 13, 2012.
Horsely L. CDC updates guidelines for the preventions of perinatal GBS disease. Am Fam Physician. 2011;83(9):1106-1110.
American Academy of Family Physicians website. Available at:
Accessed September 13, 2012.
Prevention of perinatal group B streptococcal disease--revised guidelines from CDC, 2010.
MMWR Recomm Rep. 2010;59(RR-10):1-36.
Screening and monitoring during pregnancy. EBSCO DynaMed website. Available at: http://www.ebscohost.com/dynamed/. Updated September 7, 2012. Accessed September 13, 2012.