An estimated one in five pregnant women around the world carry Group B Streptococcus (GBS) bacteria which is a major, yet preventable, cause of maternal and infant ill health globally. These are the findings of a new research supplement published in the journal Clinical Infectious Diseases.*


Led by the London School of Hygiene & Tropical Medicine and involving more than 100 researchers from around the world, this first comprehensive study of the burden of GBS, funded by a grant from the Bill & Melinda Gates Foundation, includes data and estimates for the year 2015 from every country of the world, including outcomes for pregnant women and their babies.

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Current GBS prevention focuses on giving antibiotics to women in labour, aiming to reduce disease in infants at delivery. At least 60 countries have a policy for antibiotic use in pregnancy to prevent newborn GBS disease.
Of those, 35 have a policy to test all pregnant women to see if they carry GBS, and the remaining 25 countries identify women with clinical risk factors. However, implementation of these policies varies around the world. At this time there is no policy to test all pregnant women for GBS in the UK, but there is heightened awareness of its significance.


GBS is carried by up to a third of adults, usually with no symptoms. In women, GBS can live harmlessly in the digestive system or lower vaginal tract, from where it can be passed to the unborn baby through the amniotic fluid or to newborns during labour. Babies are more vulnerable to infection as their immature immune systems cannot fight off the multiplying bacteria. If untreated, GBS can cause serious infections, such as meningitis and septicaemia, which may lead to stillbirths, and newborn and infant deaths. If they survive, babies can develop permanent problems including hearing or vision loss, or cerebral palsy.


GBS is the most common cause of severe infection in newborn babies and of meningitis in babies under 3 months old. Most early onset GBS infections (in babies aged 0 - 6 days) can be prevented by giving intravenous (not oral) antibiotics during labour to women whose babies are at raised risk of GBS infection.


 *Clinical Infectious Diseases, Volume 65, Issue Suppl_2, 6 November 2017, Pages S89–S99


1 What should you do during a woman’s pregnancy?

  • Provide all pregnant women with a patient information leaflet about group B Strep. A suitable leaflet has been produced jointly by the RCOG and Group B Strep Support and is available from
  • If a woman has had a GBS urinary tract infection (>105 cfu/ml) during her pregnancy, treat her at diagnosis with oral antibiotics, and make sure also to offer her IV antibiotics in labour.
  • Treating GBS found on a vaginal or rectal swab is not recommended in pregnancy before labour starts. The woman should be offered IV antibiotics when labour starts.


2 Who should be offered antibiotics in labour?

Women should be offered antibiotics effective against GBS in labour who:

  • carried GBS in a previous pregnancy (or alternatively testing – see below)
  • had a previous baby who had GBS infection.
  • had GBS in her urine during the pregnancy.
  • had GBS found on a vaginal or rectal swab (via an NHS or other test).
  • are in preterm labour (before 37 completed weeks).
  • have a temperature of 38°C or greater (in which case, offer broad-spectrum antibiotics that also cover GBS).


3 When is an offer of antenatal testing appropriate?

If a woman carried GBS in a previous pregnancy and the baby did not develop GBS disease, an Enriched Culture Medium (ECM) swab test for GBS carriage at 35-37 weeks (or earlier if preterm delivery is anticipated) should be offered.

  • The ECM test is not the same as a standard swab for a vaginal discharge. Swabs should be taken both from the low vagina and rectum, with samples cultured using enriched culture media and processed ASAP. You should specifically state ‘test for GBS’ on the request form.
  • If positive, the woman should be offered antibiotics in labour. If negative, she can be reassured that the risk of early onset neonatal GBS disease is very low (about 1 in 5,000). If she declines the test, she should be offered antibiotics in labour.


Group B Strep (Lower vaginal and lower rectal culture swabs, collected from 35 weeks)


Sample Reqs



GBS Collection Pack – Includes 2 x culture swab
and instructions for self-collection

3-4 days

Special instructions