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What is group B streptococcus infection in newborn babies?

BMJ Group Medical Reference


Sometimes, newborn babies get infected with bacteria (a kind of germ) called group B streptococcus in the first few days of their life. This infection can be serious and needs to be treated quickly. The bacteria are passed on from a mother to her baby during birth. To prevent this, women are sometimes given antibiotics during labour.

We've brought together the best research about preventing and treating this infection in newborn babies and weighed up the evidence about how to treat it. You can use our information to talk to your doctor and decide which treatments are best for you and your baby.

If a newborn baby gets an infection with a kind of germ (bacteria) called group B streptococcus, it can make them seriously ill. This infection doesn't happen often, but when it does, babies need to be treated quickly.

Most infections in newborn babies are caused by bacteria called group B streptococcus (also called group B strep or GBS). [1] Group B strep can live in your body without causing any problems. But if these bacteria spread from a mother to her baby during birth, they can cause serious illness such as: [1] [2]

You may also hear group B strep infections called strep B infections and beta strep infections or beta strep disease. Although adults can get group B strep infections, newborn babies are much more likely to get them.

There are two main types of group B strep infection in newborn babies.

Early-onset infection

If your baby gets group B strep infection in the first seven days of life, it's called early-onset infection. Doctors think that babies who get an infection soon after they are born breathed in fluid that contained group B strep during labour. [3] Early-onset group B strep infection in newborn babies can be prevented by giving women antibiotics during labour. The antibiotics kill the bacteria before they can be passed on to the baby. To learn more, see Preventing group B streptococcus infections in newborn babies.

Late-onset infections

If your baby gets group B strep infection between seven days and two months after birth, it's called late-onset infection. [1] Doctors aren't exactly certain how a baby gets late-onset infection. It seems that mothers probably pass group B strep to their babies through close physical contact. [1] [3] Giving women antibiotics during labour doesn't prevent babies getting late-onset infections.

Here we look at preventing and treating group B strep infections that babies can get in the first week of their life (early-onset infections).

Risk factors for early-onset group B strep infection

neonatal-infection_default.jpgCertain things make it more likely that your baby will get a group B strep infection soon after birth. These are called risk factors. If you have a risk factor it doesn't mean your baby will definitely get an infection. But the chance of your baby getting an infection is greater than that of another baby whose mother doesn't have any risk factors.

Your baby is more likely to get early-onset group B strep infection if: [9] [10] [11]

  • You carry group B strep (that is, you have the bacteria in your body but you don't have any symptoms of an infection)

  • Your baby is born before the 37th week of pregnancy

  • Your baby weighs less than 2.5 kilograms (5.5 pounds)

  • You have a fever when you are in labour

  • Your waters break before the 37th week of pregnancy or before labour (this is called the premature rupture of membranes)

  • You have lots of vaginal examinations (six or more) when you are in labour

  • You're having more than one baby.

Last Updated: July 17, 2013
This information does not replace medical advice.  If you are concerned you might have a medical problem please ask your Boots pharmacy team in your local Boots store, or see your doctor.

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