Group B Streptococcus

Group B Streptococcus is a type of bacteria that lives in the intestines, vagina or rectum. It is very common, has no symptoms, and it is not a problem in most healthy adults. However, if you are pregnant and you have GBS in your vagina when you deliver your baby, it can lead to complications for your newborn infant. 

What is Group B Streptococcus?

Group B streptococcus is called GBS or group B strep for short. GBS is a type of bacteria that lives on the human body and it can also be found in your intestines, rectum or vagina. It is natural, very common, and it is not a sexually transmitted infection. When you are healthy, GBS is not a problem and you do not need any treatment. The American Pregnancy Association estimates that approximately 25 percent of all healthy women carry GBS bacteria.

Babies at Risk of GBS  

If you have GBS in your vagina and you go into labour, your baby may be exposed and that's when it can become a problem. Your newborn baby can go on to become unwell with something called early-onset GBS sepsis. This is a severe infection that needs treating urgently with intravenous antibiotics in hospital. 

Most babies that get GBS from their mothers during delivery are absolutely fine. The risk of them developing early onset GB sepsis is very low. In fact, only about 1 in 200 mothers with GBS in their vagina, who do not receive treatment, will have a baby that develops early-onset sepsis. However, severe GBS infection is very serious. 

Treating Mothers with GBS 

If you know that you have GBS, or there is a chance that your baby will be at risk of GBS, you will need antibiotics in hospital when you go into labour. Your doctor will insert an intravenous drip into your arm or hand to administer penicillin. If you are allergic to penicillin, your healthcare professional can use another antibiotic instead of penicillin. Your doctor or midwife should be aware of your allergy, but it is always useful to remind them of it at the time.

The penicillin in your bloodstream will cross the placenta to your unborn baby and help him or her to fight GBS disease when he or she is born. You will need the antibiotics for at least four hours before your baby is born to give your baby the best protection from GBS disease. It is important, therefore, that you contact your doctor or midwife as soon as you go into labour or your waters break.

Mothers at Risk of Having Babies with GBS Infection 

You will know you have GBS in your vagina if your doctor or midwife has found it on a vaginal swab or in your urine. Some hospitals test all pregnant women for GBS at around 36 weeks and some do not. The reason that not all hospitals test for GBS is because:

  • Only 1 in 5 women who are tested for GBS will be positive, which is 20 percent. 
  • The amount of babies that have a severe infection is about 1 in 200. 

You may find out you have GBS because your doctor or midwife has tested you for something else and discovered GBS. For example, if you have vaginal irritation or you think you have a urinary tract infection and your healthcare professional takes a vaginal swab, he or she might discover GBS.

You may also be at risk of GBS infection if you go into premature labour, your waters break before 37 weeks, or your waters have been broken for more than 18 hours. Other factors include mothers who develop a high temperature during labour (38º), whatever stage of your pregnancy, or mothers with children that have previously been diagnosed with severe GBS infection. 

Antibiotics During Labour 

  • If you are having a planned caesarean section without labour, you will not need treatment for GBS before your operation. 
  • If you have GBS and your waters are still intact, you will not need to be treated for GBS before you go into labour. 
  • If you have GBS, when you do go into labour, your healthcare professional will treat you with the appropriate antibiotics in hospital. 

Treating Your Baby After Birth 

If you have been treated with antibiotics for GBS, after your baby is born he or she will need careful monitoring. If you didn’t receive antibiotics during labour, your doctor will advise you on what you need to do next. 

Checks will be carried out in hospital to monitor your baby’s temperature, heart rate and breathing for about two days. If your doctor or midwife detects any signs of infection, your baby will need antibiotics. It is also important that you notify your doctor or midwife immediately if you notice anything unusual about your baby or his or her health. 

Side Effects of Antibiotics 

There are no known side effects for your baby. For mothers, there is a very small risk of a severe allergic reaction, called anaphylaxis, but this is less than 1 in 2000. Other mild side effects can include diarrhoea, nausea and rash. Receiving treatment for GBS or being told that you have GBS will not affect the way you plan to feed your baby. Your baby cannot catch GBS from breastfeeding.