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Group B streptococcal infection

7-minute read

If your baby has difficulty breathing, a high fever, is vomiting or has floppy arms or legs, this is an emergency. Call triple zero (000) and ask for an ambulance.

Key facts

  • Group B streptococcus (GBS) is a type of bacteria.
  • Many healthy people have GBS in their bodies without becoming unwell.
  • Newborn babies, pregnant women, older adults and people with a weakened immune system may become very unwell if infected with GBS.
  • Testing for GBS can be done in late pregnancy.
  • Antibiotics can be recommended during labour to reduce the risk of infection in newborn babies.

What is group B streptococcus?

Group B streptococcus (GBS or 'group B strep') is a type of bacteria. In healthy people it is commonly found in your gastrointestinal system (gut) and vagina.

Healthy people of any age can be carriers of GBS without having any symptoms or becoming unwell.

What is group B streptococcal infection?

GBS can cause infections in some people, making them unwell. GBS is the most common cause of serious infections in newborn babies. GBS can also cause infections in:

  • people who are pregnant
  • older people
  • people with diabetes
  • people with problems with their immune system

What are the symptoms of group B streptococcal infection?

GBS infections can cause a wide range of symptoms, depending on where the infection is in your body. One common symptom of GBS infection is fever.

Types of GBS infections include:

If you are pregnant, a GBS infection can cause both you and your unborn baby to become very unwell. It can lead to a urinary tract infection (UTI) or cause an infection in the fluid that surrounds your baby, known as the amniotic fluid.

GBS infections can cause your baby to become unwell shortly after they are born. Symptoms of GBS infections in newborn babies include:

  • difficulty breathing, breathing too quickly or noisy breathing
  • being very sleepy or irritable
  • not being interested in breastfeeding or drinking from a bottle
  • vomiting
  • being too hot or too cold
  • pale or mottled skin
  • floppy arms and legs

If your baby develops signs of GBS infection, they need urgent medical attention

What causes group B streptococcal infection?

GBS infections are caused by the GBS bacteria.

GBS is commonly found in healthy people. These people are not considered to be infected with GBS, but they are carriers of the bacteria. They can pass it on to other people.

Pregnant carriers of GBS can pass the bacteria on to their baby during a vaginal birth.

When should I see my doctor?

If you are concerned that you or your baby may have a GBS infection, you should see a doctor immediately.

If your baby has difficulty breathing, a high fever, is vomiting or has floppy arms or legs, this is an emergency. Call triple zero (000) and ask for an ambulance.

FIND A HEALTH SERVICE — The Service Finder can help you find doctors, pharmacies, hospitals and other health services.

How is group B streptococcal infection diagnosed?

Your doctor will ask about your symptoms and about your health in general. They will examine you (or your baby) for any signs of an infection.

Your doctor may recommend testing your blood or urine (wee) for GBS bacteria. Sometimes other body fluids are tested, depending on where your infection is.

Other tests, such as blood tests and x-rays, may also be done.

How is group B streptococcal infection treated?

GBS infections in both adults and babies can be treated with antibiotics.

If you or your baby are diagnosed with an infection, intravenous antibiotics (through a drip) will be given urgently.

Can group B streptococcal infection be prevented?

GBS infection cannot be prevented entirely, but you can reduce the risk of passing an infection on to your baby during childbirth.

Intravenous antibiotics (given through a drip) are recommended for some people during labour to help prevent GBS infection in your newborn.

Talk to your doctor or midwife about whether you are at risk and may need antibiotics during labour.

Swab testing during pregnancy

Pregnant people can be tested for GBS at around week 36 of pregnancy.

A vaginal swab — and sometimes an anal swab — are used to test for GBS. You can do this test yourself at home or at the doctor's clinic. Or you can ask your doctor or nurse to do the swab for you.

If the test is positive, intravenous antibiotics will be recommended during labour.

If your baby is born by planned caesarean section (C-section), you do not need antibiotics for GBS.

Monitoring your baby after birth

If you have antibiotics during labour, your baby will need to be monitored in hospital for signs of GBS infection. This includes regular checks of your baby's:

  • breathing
  • heart rate
  • temperature

If they show signs of GBS infection, your doctor will recommend a blood test and maybe other tests too, depending on your baby's symptoms.

Complications of group B streptococcal infection

Complications depend on the type of infection you have and where the infection is in your body.

Resources and support

If you are worried that your pregnancy or baby may be affected by GBS, call Pregnancy, Birth and Baby on 1800 882 436 to speak to a maternal child health nurse, or talk to your midwife or doctor.

You can also call the healthdirect helpline on 1800 022 222 (known as NURSE-ON-CALL in Victoria). A registered nurse is available to speak with 24 hours a day, 7 days a week.

Information in other languages

Do you prefer to read languages other than English? NSW Health has fact sheets on pregnancy screening for Group B streptococcus in different languages.

Learn more here about the development and quality assurance of healthdirect content.

Last reviewed: November 2023

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