What is GBS?

Group B streptococcus (GBS) is a common bacterium that is found in the vaginal and intestinal flora of 1 in 4 women. Women carrying the bacterium are healthy and GBS is not sexually transmitted.

In non-pregnant women GBS does not usually cause any symptoms and does not need to be treated. However, if you are carrying GBS in pregnancy, it could cause serious infection in newborn babies during, and very rarely before labour.

How is GBS found?

GBS can be found by vaginal or urine culture of pregnant women. Studies have shown that the most reliable method to detect if GBS is going to be present at birth is to check for GBS five weeks prior to delivery. It is therefore recommended that pregnant women are tested for GBS at 35-37 weeks of gestation.

What could GBS mean for your baby?

Many babies come in contact with GBS during delivery. In the majority of cases there are no complications. However, if the bacterium is transmitted to the baby during delivery, there is a small chance that the baby gets infected and become seriously ill.

In the UK 1 in 2000 newborn babies are diagnosed with early-onset GBS infection. With prompt treatment the majority (7 in 10) are going to fully recover. However, 2 in 10 babies might recover but will have a long-term disability, and 1 in 10 will die.

When a baby is at increased risk of developing GBS infection?

  • If the baby is born preterm (<37 weeks of gestation)
  • If you had in the past a baby that developed GBS infection
  • If you had pyrexia in labour
  • If your waters have broken >18 hours before the delivery of your baby

How can we reduce the risk for your baby?

  • Vaginal and urine cultures of the pregnant woman is recommended to test if she is a GBS carrier. The cultures could be negative in the beginning of pregnancy and become positive in the end. Therefore it is recommended that women are tested for GBS at 35-37 weeks of gestation.
  • If the woman is a GBS carrier it is recommended that she receives intravenous antibiotics during labour.
  • If the pregnant woman has urinary infection due to GBS she needs to be treated promptly and to receive intravenous antibiotics in labour.
  • If in the past the woman had a baby that developed GBS infection it is recommended that she has intravenous antibiotics in labour.
  • If the woman is >37 weeks of gestation and there is rupture of membranes, labour augmentation is recommended in order to reduce the period that the fetus might come in contact with GBS. Furthermore intravenous antibiotics need to be given in labour.

The antibiotic of choice is the penicillin. However, if the woman is allergic to penicillin an alternative treatment needs to be given.

Do you need to take antibiotics during pregnancy?

Antibiotics are not recommended during pregnancy as they do not reduce the risk of GBS colonization during labour. Antibiotics are indicated only if the bacterium is found in the urine.
If you deliver by elective Caesarean Section, you will receive broad-spectrum antibiotics that cover for possible infections, including GBS.

Do you need to be delivered by elective Caesarean Section?

GBS colonization is not an indication for elective Caesarean Section. Intravenous antibiotics in labour can effectively protect the fetus.

Is breastfeeding permitted?

Breastfeeding is safe as there is no data that it increases the chances that the fetus gets infected by GBS. On the contrary, breastfeeding protects for many other infections.

For more information you could visit the following website: www.rcog.org.uk