What is group B streptococcus (strep b or GBS) and how will it affect me, or my baby, during pregnancy?
Group B streptococcus (GBS) is a bacteria that can live in our bodies quite harmlessly but it can pose a problem for pregnant women because of the risk of passing it to your baby during delivery.
At a glance
- Group B strep is a bacteria that can harmlessly live in our bodies
- If detected during your pregnancy, you'll be offered intravenous antibiotics in labour to protect your baby
- Most babies are unaffected by the bacteria and have no problems after birth
Who does it affect?
Around 25% of mums-to-be will carry the group b streptococcus bacteria in their vagina or digestive system without any cause for concern, but some mums and babies will be at more risk from the infection than others.
If you carried GBS in your previous pregnancy, there is a 50% chance of carrying GBS in the next pregnancy.
GBS infection is more likely if:
- Your baby is born prematurely (before 37 weeks of pregnancy)
- You have previously had a baby who developed GBS infection
- You have a high temperature during labour
- More than 18 hours have passed between your waters breaking and your baby being born
How is it tested for?
GBS can be detected in a urine sample, a vaginal or rectal swab. However, within the UK, testing for GBS is not routinely offered in the NHS; it is more likely to be detected if a vaginal swab or urine is taken for other reasons, but this is a non-specific test and will not identify every woman carrying GBS. The specific test to detect GBS carriage is the Enriched Culture Medium (ECM) Test, not yet universally available within the NHS but it is available privately.
Will it harm my baby?
It might be decided to give you an intravenous antibiotic drip once you are in labour to stop your baby picking up the infection during delivery. Although it sounds very serious and worrying, it is worth bearing in mind that most babies are unaffected by the bacteria and have no problems after birth.
In rare cases, GBS infection in newborn babies can cause life threatening problems, and even more rarely, it could cause miscarriage, premature labour or stillbirth.
If your baby does pick up a GBS infection – and those babies who do, tend to develop the symptoms within 12 hours of birth – it is highly likely they will make a full recovery. Only one-in-five who survive the infection will be left with a permanent health issue.
Sometimes babies can develop GBS seven or more days after birth. In these circumstances, it is likely they caught the infection from someone else, rather than from you during delivery.
If you are worried about GBS, or have been told you have it, you can get more information and advice from the Group B Strep Support organisation.