Group B Strep


What is GBS?  It's a bacteria that lives harmlessly in about 30% of adults, along with lots of other bugs.  Carrying GBS is normal and is not the same as being infected.  Where GBS can cause problems is when some babies can pick up the bug and get an infection.  GBS infections can be very serious, causing blood poisoning, pneumonia and meningitis.  GBS is the main cause of serious infections in newborn babies and with good medical care, most will recover fully.  However, sadly, even with the best medical care, about one in every 10 babies sick with GBS infection will die and others will suffer long term problems. 

How can GBS infections be prevented? The first thing is to find out if you are a GBS carrier.  If you aren't a carrier, then the chance of your baby developing a GBS infection at birth is incredibly small.  If you are a carrier – and 25-30% of us are - you can then have antibiotics in labour which will dramatically reduce any risk. 

How do you find out if you are a GBS carrier?  There are safe, sensitive tests to detect GBS carriage.  Unfortunately, these tests are not available in most NHS hospitals but they can be bought privately from a number of laboratories for around £35.  Those which follow the Health Protection Agency’s guidelines are listed at  The test kit is sent out in the post to you, then you take the swabs (low vaginal and rectal swabs – instructions included) and send them back with your payment, and then you are notified of the result a few days later.  There are no risks associated with taking the test. 

When should the test be done?  The test for GBS carriage is usually recommended between 35 and 37 weeks.  GBS carriage can come and go, so it’s important to test for it in the last few weeks before giving birth – research has shown that whatever result you get from a sensitive test is hugely likely to be the same for at least 5 weeks. (The only risk of testing later is that the baby might arrive before the test result.) 

Why does this test have to be done privately?  Unfortunately, although a few NHS hospitals offer to test women for GBS, the test they usually offer wasn't designed for detecting GBS and aren’t very sensitive so they miss lots of women carrying GBS.  A positive NHS test is reliable, but a negative one may not be.  So if you are offered a GBS test in an NHS hospital, make sure it is a sensitive enriched culture medium test with swabs taken from both the lower vagina (not HVS) and the rectum. 

What if you go into labour and you haven’t got a test result?  Then in the UK hospitals will assess you to see whether any of the recognised higher risk situations exist to determine whether you should be offered antibiotics in labour.  The Royal College of Obstetricians & Gynaecologists’s current recommendations are to offer antibiotics in the following recognised higher-risk situations: 

  • GBS has been detected (see above) during this pregnancy from vaginal / rectal swabs (any method) or from a urine sample
  • Mum has previously had a baby who developed GBS infection
  • Mum’s temperature is 37.8°C or higher during labour
What else should I know?
  • Oral antibiotics taken during pregnancy won't prevent GBS infections in newborn babies
  • Caesareans won't prevent all GBS infections in newborn babies, but may be recommended for other reasons
  • babies can develop GBS infection for several months after birth although after age 3 months they are incredibly rare.   Unfortunately, there’s no way of knowing which ones are at risk.  GBS can be passed by skin to skin contact, so make sure that everyone washes their hands before handling a baby under 3 months of age.
Group B Strep Support (GBSS) is a national charity, set up in 1996 to:
  • inform healthcare professionals how to prevent most group B Streptococcal (GBS) infections in newborn babies. 
  • offer information and support to those affected by GBS, and
  • generate continued support for research into the prevention of GBS infections in babies
Group B Strep Support (GBSS) wants all health professionals involved in maternity care to have high-quality information on preventing GBS infection in newborn babies so they can best advise the families in their care.  GBSS wants reliable screening tests (currently only readily available privately) to be freely available to all pregnant women. For more information, visit