What is group B Streptococcus (Strep B or GBS) and how will it affect me, or my baby, during pregnancy and after the birth?
Group B Streptococcus (GBS) is a bacterium 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 around labour and delivery which can cause serious infection.
At a glance
- Group b strep is a bacteria that can harmlessly live in our bodies
- Your midwife will be able to test for it and you will be given antibiotics to treat it
- Most babies are unaffected by the bacteria and have no problems after birth
Who does it affect?
Around 20-30% of mums-to-be will carry the group B Streptococcus bacteria in their vagina and/or digestive system without any cause for concern. Some babies are known to be at higher risk from the infection than others.
If you've had a previous baby who was infected with GBS, there is a 10 fold risk increase for your next baby, and if you have been found to carry GBS in this pregnancy or the bacteria has been detected in your wee at any point during this pregnancy, the risk of your newborn baby developing a GBS infection is increased 3-4 fold.
How is it tested for?
GBS can be detected on urine tests, vaginal and rectal swabs and may be found incidentally on tests performed in the NHS although these tests do not identify all carriers of GBS.
Privately paid for sensitivity tests (not widely available in the NHS) are available for around £40 and the suggested time for testing is 35 -37 weeks. Called ECM tests, they have been found to be a reliable predictor of your carriage status for the following 5 weeks.
Not all NHS Trusts use the GBS-specific testing method described in the standard by Public Health England – the Enriched Culture medium (ECM) test, so it’s wise to check. Many hospitals don’t have access to this test, so you may want to consider testing privately.
What should happen if it’s found during this pregnancy?
If GBS is detected from a vaginal or rectal swab, you should be offered intravenous antibiotics in labour to reduce the chances of your new baby getting the infection.
If you have had a group B streptococcal urinary tract infection with GBS (cystitis) during the pregnancy, you should be given oral antibiotics when it is diagnosed and then also be offered intravenous antibiotics in labour.
Will it harm my baby?
You may be offered an intravenous antibiotic drip once you are in labour to reduce the chances of your baby developing GBS infection around 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 and stillbirth.
If your baby does develop a GBS infection – and those babies who do, usually develop the symptoms within 12 hours of birth – it is highly likely they will make a full recovery. Nine out of ten babies who develop GBS infection recover, yet one in fourteen of the survivors are left with a permanent health issue. Sadly, even with the best medical care, one out of every 10 babies who develop a GBS infection dies.
Less frequently, babies can develop GBS infection seven or more days after birth (GBS infections are very rare indeed after 3 months of age. In these circumstances, it is just as likely that they picked up the bacteria from someone else, rather than from you around delivery.
If you are worried about GBS, or have been told you carry it, talk to your midwife or doctor. You can get more information and advice from Group B Strep Support charity.