Pregnancy conditions

It can be one of the most dangerous complications in pregnancy but mums to be often don’t know about it. Here’s the lowdown.

What is Group B Streptococcus (GBS)?

Group B Streptococcus is also known as GBS, Strep B or Group B Strep. It is a common bacterium that normally causes no harm (NHS Choices, 2018). The issue comes if you have Group B Streptococcus when you’re pregnant or have just had a baby (RCOG, 2017).

In the UK, 20% to 40% of women carry GBS in their vagina and rectum. You’re unlikely to know you carry it (RCOG, 2017).

Group B Streptococcus and pregnancy

If you have Group B Streptococcus, your baby will be exposed to it around labour and birth. While most babies won’t be affected, there is a small chance of your baby becoming seriously ill or even dying. In extremely rare cases GBS infection can cause miscarriage, early labour or stillbirth (NHS Choices, 2015).

The risk of your baby getting GBS infection is higher if:

  • your baby was born before 37 weeks (the risk is higher the more premature they were)
  • you previously had a baby who developed GBS infection
  • you had a high temperature during labour
  • you had any positive urine or swab tests for GBS in this pregnancy
  • your waters broke more than 24 hours before your baby was born.

Early-onset Group B Streptococcus

Early-onset GBS in newborns begins in the first week after birth. Most of these infected babies develop symptoms within 12 hours of birth.

Symptoms and signs of GBS are:

  • being floppy and unresponsive (in which case, you should dial 999)
  • not feeding well
  • grunting, noisy breathing, moaning, problems in breathing properly
  • high or low temperature
  • fast or slow heart rates
  • fast or slow breathing rates
  • irritability
  • crying inconsolably
  • changes in their skin colour, including blotchiness
  • low blood pressure
  • low blood sugar (NHS Choices, 2015; RCOG, 2017).

You should contact your GP as soon as possible if you notice any of these signs or are worried about your baby. Early treatment can be lifesaving (RCOG, 2017).

Late-onset Group B Streptococcus

Late-onset GBS usually develops seven or more days after a baby is born. This condition is not associated with pregnancy so your baby has probably been infected after birth from someone else.

Group B Streptococcus infection complications

Most babies with GBS infection can be treated successfully and will make a full recovery. However, sometimes the infection can lead to life-threatening complications like:

  • blood poisoning (septicaemia)
  • pneumonia
  • meningitis (NHS Choices, 2015).

One in 10 babies born with GBS will die from the infection and another one in five babies who survive the infection will be affected permanently. The complications of early-onset GBS include cerebral palsy, deafness, blindness and serious learning difficulties (NHS Choices, 2015).

Rarely, GBS can cause infection in the mother’s womb or urinary tract, or can cause an infection of the blood called sepsis (NHS Choices, 2015; NHS Choices, 2018).

Group B Streptococcus testing in the UK

At the moment, the NHS does not routinely test for GBS in pregnant women (RCOG, 2017; NHS Choices, 2018). This is because: it’s uncommon for GBS to give your baby an infection; tests are not accurate enough; and many babies affected by it are born earlier than when they’d be screened (RCOG, 2017).

Some women may choose to get tested and pay to do that privately (NHS Choices, 2018).

Reducing the risk in newborn babies

You will be offered antibiotics through a drip during labour if:

  • you have tested positive for GBS
  • GBS has caused a urine infection
  • you previously had a baby diagnosed with GBS infection
  • your waters break after 37 weeks and you know you carry GBS (in such cases, you’ll be induced)
  • you develop any infection during labour, even if it is not confirmed that you carry GBS
  • your labour starts before 37 weeks.

Giving birth

If you are infected with GBS, you need to discuss with your midwife where you’ll give birth. This is to make sure that antibiotics are available during labour. It might be tricky to provide antibiotics at home or in some midwifery-led units.

If you go into labour or your waters break, make sure you contact your midwife so they can make sure you get antibiotics as soon as possible. Always tell your midwife or doctor if you previously had a baby with a GBS infection or if you tested positive for GBS during this pregnancy.

Tests and treatment for babies

To check whether your baby is affected by GBS, a sample of their blood or the fluid from around their spinal cord will be taken. If your doctor suspects your baby has GBS, they’ll be treated with antibiotics immediately.


Breastfeeding your newborn baby is safe even if there are signs of GBS infection. Breastfeeding has not been shown to increase the risk of GBS infection (RCOG, 2017).

This page was last reviewed in May 2018

Further information

Our support line offers practical and emotional support with feeding your baby and general enquiries for parents, members and volunteers: 0300 330 0700.

We also offer antenatal courses which are a great way to find out more about birth, labour and life with a new baby.

Make friends with other parents-to-be and new parents in your local area for support and friendship by seeing what NCT activities are happening nearby.

For more information, visit the Group B Strep Support website here.

RCOG. (2017) Group B Streptococcus (GBS) in pregnancy and newborn babies. Available from: [Accessed 8th April 2018].

NHS Choices. (2015) What are the risks of group B streptococcus (GBS) infection during pregnancy. 2015. Available from: [Accessed 8th April 2018].

NHS Choices. (2018) Group B Strep. Available from: [Accessed 8th April 2018].

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