What is Group B Strep and how can it effect your pregnancy


Group B Strep (GBS) is a type of bacteria that can live in our bodies, often found in the vagina. It is a common bacteria, around 1 in 10 people will have it and it is usually harmless. GBS has no symptoms so the only way to find out if you are carrying GBS is through testing. Currently the UK does not offer routine testing for pregnant women. This is because GBS can come and go, so a negative result at the time of testing cannot guarantee you would not have GBS at the time you give birth. Likewise, a positive result at testing would not guarantee you are still positive at the time of birth, therefore many women and babies would receive treatment they didn’t need.

Many women carry GBS and in the majority of cases their babies are born healthy. However there is a small risk of passing on the GBS bacteria to your baby during the birth which can make them unwell, the incidence of this is around 1 in 1750 births.

If you are known to be a carrier of GBS you will be offered antibiotics when you go into labour to reduce the transmission from you to your baby. Your baby will be monitored for any signs of infection for 12 hours after birth, they will stay with you for this. If they do develop any signs of infection then they will also be given antibiotics. Usually if your baby has been infected with GBS they would develop signs and symptoms soon after birth, but occasionally they can develop the symptoms up to 3 months after birth. Signs to look out for which may indicate that your baby is becoming unwell are:

  • Pale, floppy and unresponsive
  • Unusually high or low temperature
  • Fast breathing or very slow breathing
  • Making unusual grunting sounds.

If your baby does appear to be unwell then seek medical advice immediately.

If you have previously had GBS or are concerned then please talk to your midwife or doctor and discuss the options available on the NHS and through private testing. Testing is usually done around 36 weeks pregnant so have this discussion before this stage of your pregnancy.