Group B Strep (GBS)
Understanding the Test and Protecting Your Newborn
As you enter the final weeks of your pregnancy, our clinical focus shifts toward the safety of the birth process. One of the most important routine screenings we perform between 35 and 37 weeks is for Group B Streptococcus (GBS). While many women have never heard of GBS until this point, it is a piece of information that allows us to take simple, effective steps to protect your baby from a rare but serious infection during delivery.
As an obstetrician, my role is to provide you with clear, evidence-based information about GBS. I understand that the idea of "bacteria" during birth can be concerning, but through routine screening and proactive management, we can virtually eliminate the risk of early-onset GBS infection in your newborn.
What is Group B Strep (GBS)?
Group B Streptococcus is a type of bacteria that naturally lives in the digestive tract and the vagina of about 20–25% of healthy pregnant women. It is not a sexually transmitted infection, and it is not a sign of poor hygiene. Most women who "carry" GBS (known as being colonized) have no symptoms and feel perfectly well.
The concern is not for the mother, but for the baby. During a vaginal birth, the baby can come into contact with the GBS bacteria as they pass through the birth canal. While most babies exposed to GBS remain healthy, a very small number can develop a serious infection in their first week of life, which can lead to complications such as sepsis (blood infection), pneumonia, or meningitis.
The Screening Process: Simple and Non-Invasive
In accordance with RANZCOG guidelines, I recommend a GBS screen for all expectant mothers in late pregnancy.
The Swab: The test involve a simple swab of the lower vagina and the anorectal area. It is quick, painless, and does not require a speculum.
Self-Collection: Many women find it more comfortable to collect the swab themselves in the privacy of the clinic bathroom. This is a clinically valid method and is just as accurate as a doctor-collected swab.
Why 35–37 weeks? GBS can come and go. Testing in this window provides the most accurate "snapshot" of whether the bacteria will be present at the time of your labour.
Management: Protecting Your Baby During Labor
If your result is positive, it does not mean your baby is sick. It simply means we have identified a risk that we can now manage. The standard of care for a GBS-positive mother is to receive Intravenous (IV) Antibiotics once labour has started or if your waters break.
Penicillin: This is the most effective antibiotic for GBS. If you are allergic to penicillin, we have safe and effective alternatives available.
The "4-Hour Window": Research shows that antibiotics are most effective at protecting the baby if the first dose is given at least four hours before the birth. This is why I ask GBS-positive patients to contact the hospital early once labor begins.
Planned Caesarean: If you are having a planned C-section and your waters have not broken, the risk of the baby being exposed to GBS is extremely low, and antibiotics for GBS are usually not required.
Can I Still Have the Birth I Want?
A positive GBS result should not significantly change your birth plan. You can still aim for a natural vaginal birth, use a birthing pool (in most facilities), and have immediate skin-to-skin contact with your baby. The only difference is the presence of an IV drip for the administration of the antibiotics.
Frequently Asked Questions about GBS
Q: What if I don't want to take antibiotics?
A: While the risk of a baby getting sick from GBS is low (about 1 in 200 without antibiotics), the consequences of the infection can be very severe. We will have a detailed discussion about the risks and benefits so you can make an informed, individualized choice for your baby.
Q: If I had GBS in my last pregnancy, will I have it this time?
A: Not necessarily. Your GBS status can change between pregnancies. However, if you have previously had a baby who suffered a GBS infection, RANZCOG guidelines recommend that you receive antibiotics in all subsequent labors as a safety precaution, regardless of your swab result.
Q: What are the signs of GBS infection in a newborn?
A: Our hospital paediatricians and midwives monitor your baby closely after birth. Signs include grunting while breathing, poor feeding, lethargy, or a high/low temperature. Most GBS infections (about 90%) show symptoms within the first 24 hours.
Q: If I had GBS in a previous pregnancy, will I have it again?
A: Not necessarily, but the risk is higher. If you have previously had a baby who suffered from a GBS infection, RANZCOG guidelines recommend that you receive antibiotics in all subsequent labors, regardless of your current swab result.
Q: What if I am allergic to Penicillin?
A: This is a very common concern. If you are allergic to penicillin, we use alternative antibiotics (such as Clindamycin or Vancomycin) that are equally effective at protecting your baby from GBS.
Q: What if I go into labor before I get my GBS results?
A: If your GBS status is unknown and you go into labor prematurely (before 37 weeks) or if your waters have been broken for a long time, we generally advise "prophylactic" antibiotics as a safety precaution.
Q: Does the GBS swab hurt?
A: No. The swab is very similar to a standard cotton bud and only needs to touch the surface of the skin and the lower vagina. It does not require a speculum (the metal or plastic tool used for Pap smears).
Expert Obstetric Guidance for a Safe Arrival
As a highly qualified obstetrician, my goal is to blend technical clinical safety with a supportive, patient-centered approach. I provide a safe environment where we can discuss your GBS results and address any concerns you have about the use of antibiotics. My approach is entirely individualized; I listen to your birth preferences and ensure that our safety protocols integrate seamlessly with your goals.
By identifying GBS early and providing expert management during labour, we work together to ensure your baby has the healthiest possible start. Whether your journey has been straightforward or complex, you can trust that I am providing the highest standard of evidence-based care to protect you and your newborn. Your peace of mind and your baby's safety are the heart of my practice.