Group B Streptococcus (GBS) is a type of bacteria that is found naturally in the digestive tract and birth canal in about one in four pregnant women. It is important to raise awareness of this strain of bacteria because a mother can pass it to her baby during delivery or during the baby's first six months of life.
Why Am I Having This Test?
Routine testing, also called screening, for GBS is recommended for all pregnant women between the 36th and 37th week of pregnancy. GBS is a type of bacteria that can be passed from mother to baby during childbirth. Screening will help guide whether or not you will need treatment during labour and delivery to prevent complications such as:
- An infection in your uterus during labour.
- An infection in your uterus after delivery.
- A serious infection in your baby after delivery, such as pneumonia, meningitis, or sepsis.
GBS screening is not often done before 36-weeks of pregnancy unless you go into labour prematurely.
What Happens If I Have Group B Streptococcus?
If testing shows that you have GBS, your healthcare provider will recommend treatment with IV antibiotics during labour and delivery. This treatment significantly decreases the risk of complications for you and your baby.
If you have a planned C-section and you have GBS, you may not need to be treated with antibiotics because GBS is usually passed to babies after labour starts and your water breaks. If you are in labour or your water breaks before your C-section, it is possible for GBS to get into your uterus and be passed to your baby, so you might need treatment.
Is There A Chance I May Not Need To Be Tested?
You may not need to be tested for GBS if:
- You have a urine test that shows GBS before 36 to 37 weeks.
- You had a baby with GBS infection after a previous delivery.
In these cases, you will automatically be treated for GBS during labour and delivery.
What Is Being Tested?
This test is done to check if you have GBS in your vagina or rectum.
What Kind Of Sample Is Taken?
To collect samples for this test, your health care provider will swab your vagina or rectum with a cotton swab. The sample is then sent to the lab to see if GBS is present.
What Happens During The Test?
- You will remove your clothing from the waist down.
- You will lie down on an exam table in the same position as you would for a pelvic exam.
- Your healthcare provider will swab your vagina and rectum to collect samples for a culture test.
- You will be able to go home after the test and resume all your usual activities.
How Are The Results Reported?
The test results are reported as positive or negative.
What Do The Results Mean?
- A positive test means you are at risk for passing GBS to your baby during labour and delivery. Your health care provider will recommend that you are treated with an IV antibiotic during labour and delivery.
- A negative test means you are at very low risk of passing GBS to your baby. There is still a low risk of passing GBS to your baby because sometimes test results may report that you do not have a condition when you do (false-negative result) or there is a chance that you may become infected with GBS after the test is done. You most likely will not need to be treated with an antibiotic during labour and delivery.
Talk with your healthcare provider about what your results mean.
Questions To Ask Your Healthcare Provider
Ask your healthcare provider, or the department that is doing the test:
- When will my results be ready?
- How will I get my results?
- What are my treatment options?
- Routine testing (screening) for group B streptococcus (GBS) is recommended for all pregnant women between the 36th and 37th week of pregnancy.
- GBS is a type of bacteria that can be passed from mother to baby during childbirth.
- If testing shows that you have GBS, your healthcare provider will recommend that you are treated with IV antibiotics during labour and delivery. This treatment almost always prevents infection in newborns.
This information is not intended to replace advice given to you by your healthcare provider. Make sure you discuss any questions you have with your health care provider.
ACOG Committee Opinion Number 782: Prevention of Group B Streptococcal Early-Onset Disease in Newborns. The American College of Obstetricians & Gynecologists, 2019.
Kobayashi M, Schrag SJ, Alderson MR, et al: WHO consultation on group B streptococcus vaccine development: report from a meeting held on 27-28 April 2016.
Kwatra G., Cunnington M.C., Merrall E., et al: Prevalence of maternal colonisation with group B streptococcus: a systematic review and meta-analysis. Lancet Infect Dis 2016; 16: pp. 1076-1084
Prevention of early-onset neonatal Group B Streptococcal disease: green-top guideline No. 36. BJOG 2017; 124: pp. e280-e305
Seale AC, Bianchi-Jassir F, Russell NJ, et al: Estimates of the burden of group B streptococcal disease worldwide for pregnant women, stillbirths, and children. Clin Infect Dis 2017; 65: pp. S200-S219
The Royal College of Obstetricians & Gynaecologists. Prevention of early-onset neonatal Group B Streptococcal disease. BJOG 2017; 124: pp. e280-e305
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Updated on 14 August 2020 by CaregiverAsia.
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