What is the Group B Strep Test?


What is the Group B Strep Test?

During your research into pregnancy and birth options, or perhaps when talking to friends with babies, you may have heard of getting a Group B Strep test during pregnancy. Now you have questions! What is the GBS test for, how is it done, and what could the results indicate? (And no, it doesn’t have anything to do with strep throat!)

What is Group B Strep?

Group B Streptococcus is a type of bacteria that is normally found in the vagina and/or rectum of 1 in 4 healthy women. Typically, you do not experience any symptoms, illnesses, or complications from having this bacteria in your body. Group B Strep, or GBS, is not a sexually transmitted infection and usually doesn’t cause any problems.

Why Do We Test for Group B Strep During Pregnancy?

A newborn baby is vulnerable to infection, so if you are colonized with an overpopulation of GBS bacteria, it is possible that your baby could pick up this bacteria from your vagina or rectum during the birthing process and become sick with a GBS infection. The infection could be early-onset, with organ problems, breathing problems, and blood pressure instability being a few of the possible complications; or late-onset, with meningitis  being a possible complication. Because it’s possible to ward off infection if you are a known carrier, all pregnant women are offered the GBS test during pregnancy by their OB-GYN, Certified Nurse Midwife, or Certified Professional Midwife.

How is the Group B Strep Test Performed?

At one of your prenatal appointments, around 36 weeks’ gestation, your doctor or midwife will perform the Group B Strep test by briefly touching your vaginal and rectal area with a cotton swab. They send the swab to a lab, which will test it for the presence of GBS bacteria. They usually have the results back within a day or two, and if you test positive they may either call you or just let you know at your next appointment.

What if I Test Positive for GBS?

The current standard of practice in the United States for a positive GBS test is to provide antibiotics during labor through an IV. This will help wipe out that bacteria so the baby doesn’t pick it up when emerging from the birth canal. Testing positive is fairly common, so please do not panic: just because you test positive for GBS does not mean that your baby will get sick. It simply means that the Group B Strep bacteria is present in your body just like millions of other women. If you test positive for the presence of GBS and deliver with the antibiotics going, there is only a 1 in 4000 chance of your baby picking up the bacteria and getting sick.

Can I Refuse the GBS Test?

It’s common to be skeptical about testing, procedures, and interventions during the pregnancy and birthing phases. Additionally, fears about the overuse of antibiotics are legitimate! According to the CDC, babies born to GBS-positive mothers without antibiotics have a 1 in 200 chance of getting sick, as opposed to 1 in 4000 with antibiotics. Some people are at a higher risk than others of passing on sickness. These risk factors include preterm birth, a fever during birth, having your waters broken for more than 18 hours, or having had a previous baby with an illness from GBS. As the parent you are within your rights to choose not to do certain testing – just be sure to have an honest discussion with your medical provider and ask them to talk over the benefits and risks of each choice with you.

Doing your research on Group B Strep testing during pregnancy is definitely important, but it can also lead you down a rabbit hole of scary medical stories that will keep you up at night! If you’d like to continue reading more detailed information about this test and the effects of the Group B Strep bacteria, we recommend trying these factual and easy to understand articles from American Pregnancy and Evidence Based Birth. If you like to see what other parents are doing, here is a collection of real stories from real parents about their choices to test or not, and the outcomes (both positive and negative).