Group B strep (strep B) and pregnancy

Group B strep (also known as GBS or Strep B) is a common bacteria carried in the body. Carrying group B strep is usually harmless, but sometimes it can infect a baby around the time of labour and the early weeks after birth. GBS infection can make your baby very unwell, but with early treatment most babies will make a full recovery.

What is group B strep?

Group B strep (GBS) is a type of bacteria called streptococcal bacteria. It is one of many bacteria that normally lives in our bodies, usually in the rectum (bum) or vagina. Roughly 20 to 40 in 100 (20% to 40%) of women and birthing people in the UK carry it.

If you carry GBS, in most cases your baby will be born safely and will not develop an infection. But sometimes it can affect a baby around the time of labour and in the early weeks after birth and make them poorly. In very rare cases, it can affect a baby during pregnancy.  

GBS is not a sexually transmitted disease and most women and birthing people carrying it will have no symptoms.  

What could GBS mean for my baby?

The vast majority of babies that come into contact with GBS will stay healthy.

However, some of these babies become seriously ill. Around 1 in every 1,750 newborn babies in the UK and Ireland become unwell in the first week after birth, usually within 12-24 hours of birth. This is known as early-onset GBS infection.

GBS infection is rare after the first 2 days of a baby’s life and very rare after they are 3 months old.

GBS can cause infections such as sepsis, pneumonia and meningitis. Sadly, 1 in 19 (5.2%) of babies who develop an early-onset GBS infection die. 1 in 14 (7.4%) of babies who recover from early-onset GBS infection will have a long-term disability.

Up to 1 third of GBS infections are late onset, occurring after the baby’s first 6 days. 7.7% of babies with late-onset GBS infection will sadly die, 12.4% of babies who recover will have a long-term disability.

However, most group B Strep infections can be prevented. And, most babies who are infected will make a full recovery with early treatment.

Is my baby at risk of GBS infection?

Early-onset GBS infection is more likely if:  

A recent study has shown that rates of GBS are significantly higher in babies of Black or Asian ethnicity, compared to babies of white ethnicity.

Will I be tested for group B strep in pregnancy? 

The UK National Screening Committee does not currently recommend testing all pregnant people for GBS. This is because:

  • many women carry the GBS bacteria. In most cases, their babies are born safely and do not develop an infection
  • screening all women late in pregnancy cannot accurately predict which babies will develop GBS infection
  • no screening test is entirely accurate: a negative swab test does not guarantee that you do not carry GBS
  • many babies who are severely affected by GBS infection are born preterm, before the suggested time for screening (35–37 weeks)
  • giving antibiotics to all women who carry GBS would mean that a very large number of women would receive treatment they do not need.

You will be asked to give a sample of your urine (wee) at each antenatal appointment. This is to check for several things, including protein. If this is found, it may mean you have a urinary tract infection.  

It is not specifically tested for, but group B Strep may sometimes be found in your urine (wee).

Private testing is available which costs money. Group B Strep Support has a list of private providers that sell GBS tests and use the ‘gold standard’ Enriched Culture Medium (or ECM) test for group B Strep as recognised by Public Health England and the Royal College of Obstetricians and Gynaecologists

Urinary tract infections in pregnancy

Speak to your GP or midwife as soon as possible if you have any symptoms of a urinary tract infection. If a urine infection in pregnancy is caused by GBS, you should be treated with antibiotics straight away. You should also be offered antibiotics through a drip during labour. This will reduce the risk of your baby developing an infection.

Testing and treatment if you had GBS in a previous pregnancy

You will be offered a GBS test when you are 35-37 weeks pregnant (or 32-34 weeks of you are having a multiple pregnancy) if you carried GBS in a previous pregnancy and your baby was not affected by GBS. This is because there is a 1 in 2 (50%) chance that you will be carrying it again in this pregnancy.

If the result shows that you are still carrying GBS, the risk of your baby developing an infection is around 1 in 400. You will be offered antibiotics in labour.

If you are not still carrying GBS, then the risk of your baby developing an infection is much lower (1 in 5000).

You do not need to be tested for GBS if you have had a baby with GBS infection before. Instead, you should be offered antibiotics through a drip from the start of labour in every pregnancy after that. This will reduce the risk of your baby getting infected.

How can the risk of my baby developing GBS infection be reduced?

If your baby has a higher risk of early-onset GBS infection you may be offered a dose of antibiotics through a drip from the start of labour and at intervals until your baby is born. You will not be offered antibiotics before labour because this does not reduce the chance of your baby developing GBS infection.  

These antibiotics reduce the risk of your baby developing a GBS infection in their first week of life from around 1 in 400 to 1 in 4,000. Your healthcare professional should talk to you about the benefits and risks of taking these antibiotics.

Antibiotics do not prevent late-onset GBS infection so it is important to know the signs of infection, which are listed further below.

If you have a positive GBS test

If testing show that you are carrying GBS, you will be offered antibiotics through a drip from the start of labour and at intervals until your baby is born.  

If you have a GBS urine infection 

If you have a urine infection caused by GBS, you will be offered antibiotic tablets to treat the infection straight away. You’ll also be offered antibiotics through a drip during labour.

If your waters break after 37 weeks and you are carrying GBS

If this happens, you will be offered induction of labour straight away. This is to reduce the time that your baby is exposed to GBS before birth. You should also be offered antibiotics through a drip.  

If you develop any signs of infection in labour 

Even if you are not known to carry GBS, you will be offered antibiotics through a drip that will treat a wide range of infections including GBS.

If you go into premature labour 

If your labour starts before 37 completed weeks of pregnancy, your healthcare professional will recommend that you have antibiotics through a drip even if you are not known to carry GBS.

If you are having a planned caesarean section 

You do not need antibiotics to prevent GBS infection in your baby if you are carrying GBS and have a planned caesarean section (including a preterm section). However, if labour has started or your waters have broken, you will be offered antibiotics.  

All women having a caesarean section will be offered antibiotics at the operation. This is to reduce the risk of a wide variety of infections, including GBS.

I had tested positive for GBS during previous pregnancies, so I was offered antibiotics during labour with my youngest son. I was being induced due to an unrelated complication and had a history of fast deliveries and so was given my first dose of antibiotics before having my waters manually broken. It ended up being my only dose as our little boy was born 3 hours later. Having the drip didn't affect my labour at all, I was mobile and active during labour. It gave us enormous peace of mind to know that the antibiotics had minimised the chance of him developing a GBS related infection.


What are my options for where I can have my baby?

Your midwife or doctor will talk to you about your birth plan and where and how you want to give birth. You should always let your healthcare professional know if you have previously had a baby who had GBS infection or if you have tested positive for GBS in this or a previous pregnancy.  

If you need antibiotics during labour, they will need to be given through a drip. This means that it may not always be possible to arrange this at home or in some midwifery-led units.

Find out more about your options for where to give birth.

Having antibiotics shouldn’t stop you from moving around freely during labour or from having a water birth, if that’s what you want.  

If your waters break before labour, your healthcare professional will talk to you about when you will need antibiotics and about the best time for your baby to be born. This will depend on your individual circumstances and on how many weeks pregnant you are.  

If you know you need antibiotics in labour, contact your healthcare professional as soon as labour starts or your waters break. It is important that you have antibiotics as soon as possible.

Will my baby be monitored for GBS after they are born?

Your baby will not need special monitoring if:  

  • they are born at full term (after 37 completed weeks)
  • you had antibiotics in labour at least 4 hours before giving birth  
  • your baby appears well, with no signs of infection.

If your baby is thought to be at higher risk of GBS infection and you did not get antibiotics at least 4 hours before giving birth, they will be monitored closely for signs of infection for at least 12 hours. This will include assessing your baby’s general wellbeing, heart rate, temperature, breathing and feeding.  

If you have had a baby affected by GBS infection before, your baby will be monitored for 12 hours even if you had antibiotics in labour. 

The chance of your baby developing GBS infection after 12 hours is very low. You and your baby won’t need antibiotics after this, unless either of you become ill. 

What are the signs of GBS infection in my baby? 

Most babies who develop GBS infection become unwell in the first few weeks of life, usually within 12-24 hours of birth. With early-onset GBS infection they may have the following symptoms:

  • grunting, noisy breathing, moaning, seeming to be working hard to breathe when you look at their chest or tummy or not breathing at all  
  • be very sleepy and/or unresponsive  
  • be crying inconsolably  
  • be unusually floppy
  • not feeding well or not keeping milk down  
  • have a high or low temperature and/or their skin feels too hot or cold  
  • have changes in their skin colour (including blotchy skin)
  • have an abnormally fast or slow heart rate or breathing rate  
  • have low blood pressure or low blood sugar (tests for these are done in hospital).

Contact your local children’s A&E urgently and tell them you are concerned it may be GBS if you notice any of these signs or are worried about your baby. Tell them if there is any history of GBS. If your baby has GBS infection, early treatment will give them the best chance of recovery.  

What tests and treatments will my baby have?

If your healthcare professional thinks that your newborn baby has an infection, they will do tests to see if it is caused by GBS. This may involve doing a blood test, or a sample of fluid will be taken from around your baby’s spinal cord (known as a lumbar puncture).  

You will be asked for your consent (permission) before these tests are done.

Babies with signs of GBS infection or babies who are suspected to have the infection should be treated with antibiotics as soon as possible. Treatment will be stopped if there is no sign of infection after at least 36 hours, and all the tests are negative. 

Can I still breastfeed if my baby has a GBS infection? 

Yes, it is safe to breastfeed your baby. Breastfeeding has not been shown to increase the risk of GBS infection, and it offers many benefits to both you and your baby.

Could my baby develop GBS infection after their first week of life? 

Most GBS infections in babies are in the first week after the birth. But in the UK around a third of GBS infections in babies are late-onset, which means they happen between 6 days to 3 months after birth.

Having antibiotics during labour does not prevent late-onset GBS infection, and there are currently no known ways of preventing late-onset GBS infections.

Call 999 or go to A&E if your baby gets any of these symptoms:

  • being floppy or unresponsive
  • grunting when breathing, or working hard to breathe when you look at their chest or stomach
  • very fast or slow breathing
  • an unusually high or low temperature
  • changes in their skin colour or blotchy skin
  • not feeding well or vomiting milk up
  • an unusually fast or slow heart rate
  • irritable with high-pitched or whimpering cry or moaning
  • a tense of bulging fontanelle (the soft spot on babies’ heads)
  • turning away from bright lights
  • a blank, staring or trance-like expression
  • involuntary stiff body or jerking movements.

They may need treatment with antibiotics in hospital immediately.

Group B strep can be carried on the skin. It is a good idea for everyone to wash and dry their hands properly before they hold a baby under 3 months old. Skin-to-skin contact with your baby is still recommended. Skin-to-skin means having your baby on your chest, their naked skin next to yours, with a blanket over both of you for warmth if needed.

There are lots of reasons to have skin-to-skin contact with your baby. It can:

  • help you bond
  • calm and de-stress you both
  • help with breastfeeding
  • keep your baby warm
  • regulate your baby’s heart rate, breathing rate and blood sugars
  • comfort your baby.

More information and support

Group B Strep Support is a UK charity working to stop group B strep infections in babies. They provide up to date and evidence-based information on group B strep to new and expectant parents and their health professionals, and support to affected families.

Their leaflet Group B Streptococcus (GBS) in pregnancy and newborn babies is available in 14 languages. 

Group B Strep Support and the Royal College of Obstetricians & Gynaecologists. (Group B Streptococcus in pregnancy and newborn babies Group B Streptococcus (GBS) in pregnancy and newborn babies

O'Sullivan CP et al (2019). Group B streptococcal disease in UK and Irish infants younger than 90 days, 2014-15: a prospective surveillance study. Lancet Infect Dis. 2019 Jan;19(1):83-90. doi: 10.1016/S1473-3099(18)30555-3. Epub 2018 Nov 26. PMID: 30497953.

Collin SM et al (2022). Race and Ethnicity in Neonatal Group B Streptococcal Disease in England: 2016-2020. Pediatrics. 2022 Sep 1;150(3):e2021056080. doi: 10.1542/peds.2021-056080. PMID: 35979728.

Group B streptococcus - UK National Screening Committee (UK NSC) - GOV.UK (

NHS. Group B strep. (Page last updated 12 March 2021 Next review due: 12 March 2024)

Royal Berkshire NHS Foundation Trust (2023) Skin-to-skin contact and why it is important

Group B Strep Support. Symptoms of group B strep infections in babies.

Review dates
Reviewed: 19 September 2023
Next review: 19 September 2026