Group B Strep: all your questions about strep B answered

  • We earn a commission for products purchased through some links in this article.
  • Group B Strep is an infection that most mums have never even heard of, but every year, 700 newborn babies get seriously ill because of it.

    The bacterial infection can cause meningitis, pneumonia and blood poisoning in newborn babies.

    As it stands, the UK does not offer routine tests to pregnant women to check for group B Strep, despite it being the most common cause of severe bacterial infection in newborns.

    Around one in 1000 babies born in the UK picks up a group B Strep infection – roughly the same number as are affected by Down’s Syndrome and spina bifida, both of which pregnant women are told about and offered a screening test for. In fact, in a recent magazine survey, nine out of 10 women hadn’t heard of group B Strep.

    What is group B Strep?

    Group B Strep (GBS) is a type of bacteria carried by one in three of all adults in their intestines, and up to one out of four women carry GBS in their vagina.

    Most people who carry GBS aren’t aware of it, as carrying it causes no symptoms.

    If a pregnant woman is carrying GBS, her baby may be exposed to the bacteria around labour and delivery. For most babies this causes no problems, for others it can be deadly; causing meningitis, pneumonia and blood poisoning.

    Every year in the UK 75 sick babies die and 40 are left with permanent problems as a result of contracting Group B Strep at birth. Group B Strep can be contracted through skin-to-skin contact or close physical contact. GBS is not a sexually transmitted disease, carrying it causes no symptoms, and it doesn’t need treatment. It’s normal.

    How do I know if I have group B Strep?

    Group B Strep carriage can come and go – a sensitive swab test at 35-37 weeks will give the best idea as to whether a woman will be carrying GBS at delivery.

    The NHS does not routinely test for GBS, and when it does, the swab test normally used gives falsely negative results to up to half the women carrying GBS.

    A more reliable test, called an Enriched Culture Medium (ECM) test, is only available in a few NHS hospitals, although it is available privately. Contact the charity, Group B Strep Support for more information.

    What are the chances of me passing it on to my baby?

    If no preventative measures are taken, the risk of GBS infection in newborn babies is:

  • 1 in 1,000 where the woman is not known to be a carrier of GBS
  • 1 in 300 where the woman is carrying GBS at delivery
  • 1 in 100 where the woman has had a previous baby infected with GBS.
  • Recent UK research has suggested GBS infection in newborn babies could be as high as 3.6 per 1,000. If a woman who carries GBS is given antibiotics in line with recommendations, the risk is far lower:

  • 1 in 6,000 where the mother carries GBS at delivery
  • 1 in 2,200 where the mother has previously had a baby infected with GBS
  • Can it be prevented?

    Yes, if you have had any positive GBS test result during the current pregnancy, you should be offered a drip containing antibiotics once labour starts and at intervals until the baby’s delivered. If GBS was found in a urine sample, oral antibiotics will be prescribed at the time, and again if you are offered an antibiotic drip when you’re in labour.

    Having a Caesarean section won’t necessarily protect against GBS infection, plus the operation carries significant risks of its own.

    Giving antibiotics during labour to women at higher risk of passing on the bacteria would prevent more than 80% of GBS infections in newborn babies.

    What are the symptoms in babies?

    Most babies born with Group B strep develop tell-tale symptoms at around the 12-24 hour mark, after birth. However these can sometimes be hard to spot. Symptoms include:

  • Being floppy and unresponsive
  • Not feeding well
  • Grunting
  • High or low temperature
  • Fast or slow heart rates
  • Fast or slow breathing rates
  • Irritability
  • What are the potential risks of antibiotics?

    The estimated risks for mother’s taking penicillin are:

  • 1 in 10 mothers develop a mild allergic reaction, such as a rash
  • 1 in 10,000 mothers develop a severe allergic reaction (anaphylaxis)
  • 1 in 100,000 mothers develop fatal anaphylaxis, resulting in her death (however, in the US between 1997 and 2001, an estimated 1.8 million women were given penicillin in labour and no deaths were reported).
  • It is very important that you tell your nurse, doctor or midwife, if you have ever suffered any reaction to any antibiotic.

    Anaphylaxis in the mother can also cause severe complications in the unborn baby.

    Pregnant women need to weigh up the risks and potential benefits, and consider when they might want to have antibiotics.