GROUP B STREPTOCOCCUS (GBS)

The following information is derived from the Association of Ontario Midwives – Clinical Practice Guidelines

 

WHAT IS GBS?

GBS is a type of bacteria that is a normal part of body flora. At any given time, about 10-35% of people who are pregnant have GBS in their vagina and/or rectum. GBS is not usually harmful to an adult and most people who have the bacteria will not have any symptoms.

 

WHY ARE WE CONCERNED WITH GBS?

GBS can cause sickness in babies in their first week of life (early-onset) or after the first week (late-onset).

The most common ways that babies get GBS is from the birthing parent during labour & birth.

Though most babies are unaffected, a small number of babies exposed will develop a GBS infection. This can lead to bacteria in the blood (sepsis), lung infection (pneumonia), inflammation in the brain/spine (meningitis), respiratory infections and death. Some babies will have long-term effects.

 

WHAT INCREASES MY BABY’S RISK OF GETTING EARLY ONSET GBS?

Your baby is at higher risk of early-onset GBS disease if one or more of the following occurs:

  • You are GBS positive during labour or have GBS in your urine in pregnancy
  • Your baby is born preterm
  • Your baby weighs less than 2500 grams
  • Your water breaks more than 18 hours before you baby is born
  • You have a fever during labour
  • You had a previous baby with GBS disease

 

HOW CAN I FIND OUT IF I CARRY GBS?

Your midwife will recommend a self-administered swab around 35-37 weeks of pregnancy to screen for GBS bacteria.

It is a vaginal-rectal swab that is considered valid for 5 weeks after testing. Your midwife will explain how to do the test.

If your test comes back positive, it means you carry the GBS bacteria at that time. If the test is negative, the bacteria is not present. This test correctly identifies someone with GBS 87% of the time.

As with all tests in pregnancy, GBS screening, though recommended, is not mandatory.

 

HOW CAN WE HELP PREVENT EARLY-ONSET GBS DISEASE?

If your baby is at risk (for example, if you are GBS positive), you will be offered IV (in the vein) antibiotics during active labour.

If you choose to take the antibiotics, a dose is given every 4-8 hours until your baby is born. Most antibiotics can be administered at home, hospital or birth centre.

With all antibiotics, there is a risk of disturbing beneficial bacteria in the body which can on occasion lead to a yeast infection. In rare cases, antibiotics may cause:

  • Allergic reaction in pregnant person
  • Antibiotic resistance (creating resistant bacteria)
  • Possible increased risk of baby developing asthma or allergies.

 

WHAT ARE MY CHOICES

The two most common ways of screening for and treating GBS are:

1. Swab for GBS and receives antibiotics if GBS positive.

This option is currently the most popular in Ontario and in our community.

With this, you will be offered antibiotics during labour if you test positive for GBS at 35-37 weeks.

This choice reduces early-onset GBS disease in babies by 65-86% when compared to babies of clients who did not receive antibiotics.

2. Swab for GBS and receives antibiotics only if GBS positive AND if there is another risk factor.
With this option, you will be offered antibiotics in labour if you tested positive for GBS at 35-37 weeks AND:

  • You go into preterm labour
  • You develop a fever during labour
  • Your water breaks before labour

This choice reduces early-onset GBS disease in babies by 51-75% when compared to babies born to clients who do not receive antibiotics.

 

RISKS OF EARLY ONSET GBS DISEASE

The following graphic demonstrates a visual to help our clients understand the risks of their baby developing early onset GBS infection.

GBS stats visualization