What should I know about Group B Strep and Pregnancy?

What I should know about Group B Strep and Pregnancy?

What is Group B Strep?

The Group B Streptococcus bacteria lives in the intestines, rectum, and vagina.  Most women have no symptoms and although it is not a sexually transmitted disease it can be passed from one person to another through close physical contact.

Although GBS is rarely harmful to the mother it can pass to the baby, particularly during labour, most of the time your baby will be born safely. However, it can be passed onto your baby during birth and can occasionally cause serious infection and complications such as:

  • Sepsis - an infection of the blood
  • Meningitis - an infection of the fluid and lining around the brain, or 
  • Pneumonia - an infection of the lungs
This can be life threatening in young babies.

    GBS, Strep B, Group B Strep is also known to cause urinary tract infections, and rarely, can infect the uterus and cause late miscarriages, preterm birth, and stillbirth.

    The good news is that if detected during pregnancy, GBS infection in your newborn baby can usually be prevented with antibiotics in labour.

    The importance of testing for Group B Strep in Pregnancy

    It’s therefore important to get tested from 35 weeks onwards into your pregnancy to find out if you are carrying the bacterium.  If Strep B is found during your pregnancy, or you have previously had a baby affected by a Strep B infection you should be offered intravenous antibiotics in labour which are very effective at reducing the risk of your baby contracting a GBS infection during the vital first hours and days of life.

    However, early-onset Group B Strep infection which can develop in the first 6 days of life, usually on the first day of life is more likely if your baby is born preterm, if you have a temperature while in labour, or if your waters break before going into labour. If your newborn baby develops signs of a Strep B infection, they should be treated with antibiotics straight away.

    1 in 19 newborn babies who develop Group B Strep infection will die from the infection

    1 in 19 babies who develop a Group B Strep infection will die from early-onset GBS infection.

    Late-onset Group B Strep infection can develop in babies between 7-90 days and although much less common than an early-onset GBS infection it is more likely if your baby is born before 37 weeks of pregnancy or you have had a positive Strep B test in your pregnancy.

    1 in 13 babies that develop a GBS infection will die from late-onset GBS infection

    1 in 13 babies that develop a GBS infection will die from late-onset GBS infection.


    1 in 14 of the babies who survive a Group B Strep infection will have a long-term disability following their early-onset GBS infection and 1 in 8 following their late-onset GBS infection. You should be offered antibiotics if you develop a urine infection associated with Strep B during your pregnancy and IV antibiotics again during labour. IV antibiotics should also be offered during labour if you have had a positive Strep B test result or previously had a baby affected by GBS. If you are a known carrier of GBS and your waters break after 37 weeks you should be offered an induced labour to reduce the time your baby is exposed to GBS before birth along with antibiotics. If you develop any signs of infection in labour such as a high temperature you should be offered IV antibiotics whether you are a known GBS carrier or not.