Group B Streptococcus (GBS) - Your pregnancy and your baby

This leaflet is for pregnant women and birthing people who have had a positive result for group B Streptococcus on a swab or urine test.

What is (GBS)?

Group B Strep is a type of bacteria that is found in the intestines of about a third of all adults, and in the vagina & rectum of 2-4 in 10 (20-40%) people in the UK. GBS is not a sexually transmitted disease, and most carriers will not have any symptoms. Routine screening for GBS in all pregnant women and birthing people is not recommended in the UK. However GBS is often detected by chance through a vaginal or rectal swab, or a urine test.

Many babies come in to contact with GBS during labour or around the time of birth, and the vast majority do not become ill. There is, however, a small chance that your newborn baby will develop GBS infection and become seriously ill, or die.

The infections that group B Strep most commonly causes in newborn babies are sepsis (infection of the blood), pneumonia (infection in the lungs), and meningitis (infection of the fluid and lining around the brain).

Around 1 in every 1750 babies in the UK and Ireland is diagnosed with early-onset group B Strep infection (developing in babies aged 0-6 days).

Around 1 in every 2700 babies in the UK and Ireland is diagnosed with late-onset group B Strep infection (developing in babies aged 7-90 days).

Although group B Strep infection can make your baby very unwell, with prompt treatment most babies will recover fully.

Does my baby have a high chance of developing group B Strep infection?

Any baby can develop a group B Strep infection, but early-onset group B Strep infection (developing in the first 6 days of life, and usually on the first day of life) is more likely if:

• your baby is born preterm (before 37 weeks of pregnancy) – the earlier your baby is born, the greater the chance
• you have previously had a baby who developed a group B Strep infection
• you have had a high temperature (or other signs of infection) during labour
• you have had any group B Strep positive urine or swab test in this pregnancy
• your waters have broken more than 24 hours before your baby is born

Late-onset group B Strep infection (developing in babies aged 7-90 days) is less common than early-onset GBS infection and is more likely if:

• your baby is born preterm (before 37 weeks of pregnancy)
• you have had group B Strep positive test in this pregnancy

What is the treatment for GBS?

Most early-onset group B Strep infections can be prevented by giving intravenous antibiotics in labour to women & birthing people whose babies are at higher chance of developing the infection. At present, there are no known methods to prevent late-onset GBS infection.

• A urine infection caused by group B Strep should be treated with antibiotic tablets straight away and you will also be recommended intravenous (IV) antibiotics during labour.
• You will be recommended IV antibiotics during labour if you have had a GBS-positive swab or urine test from an NHS or other accredited laboratories during your current pregenancy.
• If you have previously had a baby who was diagnosed with GBS infection, you will be recommended IV antibiotics when you are in labour.
• If GBS was found in a previous pregnancy and your baby was unaffected, you can have swab tests taken from the vagina and rectum to see whether you are carrying GBS when you are 35-37 weeks pregnant. If the test result is positive, you will be recommended antibiotics in labour. If the test result is negative at this point, then the chance of your baby developing early-onset GBS infection is low and you may choose not to have antibiotics. Alternatively you can choose not to be re-tested in this pregnancy, and to have prophylactic IV antibiotics in labour.
• If your waters break after 37 weeks of your pregnancy and you are known to carry GBS, you will be recommended induction of labour straight away. This is to reduce the time that your baby is exposed to GBS before birth. You will also be offered IV antibiotics.
• Even if you are not known to carry GBS, if you develop any signs of infection in labour, you will be offered IV antibiotics that will treat a wide range of infections including GBS.
• If your labour starts before 37 weeks of your pregnancy, you will be recommend to have IV antibiotics even if you are not known to carry GBS.
• If your baby is going to be born by planned caesarean section and your waters do not break before the caesarean section, then you do not need IV antibiotics before your baby’s birth.

How will my newborn be monitored?

If your baby is born at full term (after 37 completed weeks) and you received IV antibiotics in labour at least 4 hours before giving birth, no special additional monitoring for group B Strep is routinely recommended after birth. If you baby is born by planned or pre-labour caesarean section then your baby will not require any additional monitoring.

If your baby is considered to be at higher chance of group B Strep infection and you did not get IV antibiotics at least 4 hours before giving birth, your baby will be monitored closely for signs of infection for at least 12 hours, but in some cases up to 24 hours. This will include assessing your baby’s general wellbeing, heart rate, temperature, breathing and feeding.

If you have previously had a baby who developed group B Strep infection, your baby will be monitored for 12 hours even if you had at least 4 hours of IV antibiotics in labour before giving birth.

If your baby shows any signs of GBS infection IV antibiotics will be recommended.

After the baby is 12 hours old, the chance of your baby developing group B Strep infection is very low and neither you nor your baby will need antibiotics unless you or your baby becomes ill.

Even though staff will be monitoring your baby closely, please be aware of the signs of GBS infection in newborns, and report to staff if you notice any of the following:

• Noisy breathing, or it looks like they’re working hard to breath
• Being very sleepy or unresponsive
• Inconsolable crying
• Being unusually floppy
• Not feeding well, or not keeping milk down
• Having a low or high temperature. Your baby’s chest should feel warm to the touch, not hot or cold
• Changes in their skin colour (including blotchy skin)

For late on-set GBS, there are some additional signs to be aware of:

• Being irritable with a high-pitched or whimpering cry
• Blank, staring or trance-like expression
• Floppy, or dislikes being handled
• Bulging fontanelle (the soft spot on top of baby’s head)
• Turning away from bright light
• Involuntary stiff body
• Jerking movvements
• Pale, blotchy skin

If you spot any of these signs, please contact your GP for an urgent appointment, or call 111. Make sure to inform them that you were diagnosed with group B Strep.

Further information about GBS can be obtained from:

NHS group B Step (opens in a new tab)

Royal College of Obstetricians and Gynaecologists (RCOG) (opens in a new tab)

Group B Strep support (opens in a new tab)

Tommy's (opens in a new tab)

References/ Sources of evidence

Royal College of Obstetricians and Gynaecologists (RCOG) (2023) Group B Streptococcus (GBS) in pregnancy and newborn babies) Group B Streptococcus (GBS) in pregnancy and newborn babies | RCOG (opens in a new tab)

Group B Strep support (2023) Group B Strep and pregnancy Group B Strep and pregnancy - Group B Strep Support (gbss.org.uk) (opens in a new tab)