Strep B (group B streptococcus) is a common bacteria. It is found in the vagina, urine or rectum (back passage).
It's usually harmless. Most people will not realise they have it.
It can be a problem:
- if you're pregnant - it could spread to the baby
- in newborn babies - it can make them very ill
- if you're elderly, or you're very ill - it can cause repeated or serious infections
This page focuses on strep B in pregnancy and babies.
Strep B in pregnancy
Strep B is common and rarely causes any harm to you or your baby.
It's not routinely tested for, but may be found during tests carried out for another reason. For example, a urine test or vaginal swab.
Risks in pregnancy
If you have group B strep while you're pregnant:
- your baby will usually be healthy
- there's a small risk it could spread to your baby during labour and make them ill - this happens in about 1 in 1,750 pregnancies
- there's a very small risk you could miscarry or lose your baby
What to do if you're worried
Speak to your midwife or GP for advice if you're worried about group B strep.
Talk to them about the risks to your baby and ask if you should get tested.
What happens if you have group B strep
If tests find group B strep while you're pregnant, or you've had a baby affected by it before, you may need extra care and treatment.
You may be advised to:
- speak to your midwife about your birth plan - they may recommend giving birth in hospital
- contact your midwife as soon as you go into labour or your waters break
- have antibiotics into a vein during labour - this can reduce the risk of your baby getting ill
- stay in hospital for at least 12 hours after giving birth so your baby can be monitored (this is not always needed)
Group B strep in babies
If you had group B strep during pregnancy, there's a small risk it could spread to your baby and make them very ill.
If this happens, it's usually soon after they're born. Your baby may be monitored in hospital for up to 12 hours to check for any problems.
They'll be given antibiotics into a vein if they develop symptoms.
Symptoms after leaving hospital
Occasionally, symptoms of a group B strep infection in a baby can develop up to 3 months after birth.
Symptoms may include:
- being floppy or not responding normally
- grunting when breathing, or visibly working hard to breathe
- very fast or slow breathing
- an unusually high or low temperature
- changes in their skin colour or blotchy skin
- not feeding well or vomiting
- an unusually fast or slow heart rate
Urgent advice: Contact your maternity unit if:
- your baby has symptoms of a group B strep infection
They may need treatment with antibiotics in hospital immediately.
Do not drive to hospital. Ask someone to drive you, or call 112 or 999 and ask for an ambulance.
Bring your own medicines with you.
Risks of group B strep in babies
Most babies with a group B strep infection make a full recovery if treated.
Some babies may develop serious problems, such as sepsis or meningitis.
This can cause lasting problems such as loss of hearing or vision. Sometimes a group B strep infection can be fatal.
Content supplied by the NHS and adapted for Ireland by the HSE
