Group B Streptococcus (GBS)

Group B Streptococcus (GBS or group B Strep) is the most common cause of severe infection in newborn babies, and of meningitis in babies under age 3 months. 

On average in the UK:

  • 2 babies a day develop group B Strep infection
  • 1 baby a week dies from group B Strep infection
  • 1 baby a week survives group Strep infection with longer disability

Most GBS infection is of early onset, presenting in babies within the first 6 days of life, and usually within the first 12 hours after birth. Between age 7 days and 3 months, these infections are rare; in babies over 3 months they are very rare indeed.

Most early-onset GBS infections (in babies aged 0–6 days) can be prevented by giving intravenous antibiotics in labour to women whose babies are at raised risk of developing GBS infection.

In the UK, women are offered intravenous antibiotics in labour based on specific risk factors. GBS is normal flora of the distal gastrointestinal tract. Up to 30% of women carry it harmlessly in their vaginal tract. Vaginal carriage at the time of vaginal delivery can result in transmission of GBS to the baby. 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. Current GBS prevention focuses on giving intravenous antibiotics to women in labour, aiming to reduce disease in infants at delivery. 

2 x Blue culture swabs (lower vaginal and lower rectal) should ideally be taken from 35 weeks. Swabs will be placed in enrichment culture in the microbiology laboratory to ensure maximal detection.