Group B Streptococcus Colonisation in Pregnancy - Management of

Publication: 07/03/2012  --
Last review: 03/10/2016  
Next review: 01/10/2019  
Clinical Guideline
ID: 2865 
Approved By: Trust Clinical Guidelines Group 
Copyright© Leeds Teaching Hospitals NHS Trust 2016  


This Clinical Guideline is intended for use by healthcare professionals within Leeds unless otherwise stated.
For healthcare professionals in other trusts, please ensure that you consult relevant local and national guidance.

Management of Group B Streptococcus Colonisation in Pregnancy

  1. Aims
  2. Background
  3. Diagnosis
  4. Management
    4.1 antenatal
    4.2 intrapartum
    4.3 postnatal
  5. Evidence Base
  6. Provenance

Appendix 1 - Flowchart for care of women at risk of neonatal GBS infection
Appendix 2 - Indication for intra-partum antibiotics
Appendix 3 - Newborn Observation Chart

See also

1.0 Aims and Objectives

The aim of this guideline is to clarify the management and treatment of women diagnosed with a Group B streptococcal infection or vaginal colonisation during pregnancy in order to prevent early onset Group B streptococcal neonatal infection

Back to top

2.0 Background

Group B streptococci (GBS) are found contaminating or as part of the vaginal flora of approximately 5-30% of pregnant women (1-4). The vast majority of these women and their babies will not develop symptomatic infections although GBS can cause a symptomatic urinary tract infection in pregnancy. In a small proportion, about 1-2%, intrapartum transmission of GBS to a new-born infant occurs and can result in early onset neonatal sepsis (5) with a mortality of approximately 10%.

EOGBS typically occurs within the first 24 hours of life (90% of cases) and accounts for approximately 30% to 50% of neonatal infections.

Several strategies have been proposed to prevent early onset neonatal disease (occurring in the first week of life) including antenatal screening, antenatal, intrapartum and postpartum treatment. None of these strategies are effective in preventing late onset disease.

Late-onset GBS disease is more commonly caused by infection from other sources, acquired in hospital or in the community.

Back to top

3.0 Diagnosis

Group B streptococcal colonisation can be identified by culture of GBS isolated incidentally from a genital tract swab or urine culture. 

Back to top

4.0 Management

4.1 Antenatal management

  • At present there is insufficient evidence to support routine antenatal screening for GBS.16
  • If GBS is isolated incidentally from genital tract swabs or urine culture in this pregnancy then this fact should be clearly documented in the woman’s case notes and a yellow sticker placed on the front of the notes (with the woman’s consent). This applies to women who have had a private screening test who should be encouraged to discuss this with their midwife
  • Women with a positive urine culture for GBS or any other organism should be treated with oral antibiotics ( but will still need intrapartum prophylaxis).
  • There is no evidence to support the use of antibiotics before the onset of labour where GBS has been isolated antenatally from the genital tract since over 70% of women so treated will recolonise within 3 weeks of treatment(6) and repeated courses of antibiotics will only increase the incidence of antibiotic resistant strains of GBS.
  • Vaginal carriage of GBS is not a contraindication to membrane sweep in the community

4.2 Intrapartum management
(See obstetric prophylaxis guidance)

Women should be informed that studies indicate that intrapartum chemoprophylaxis reduces neonatal colonization (7-11, 14) early onset neonatal disease (10-14) and postpartum maternal febrile illness (14). Therefore, it is recommended that to reduce the incidence of neonatal GBS, women should be offered intrapartum antibiotics under the following circumstances,:

  • Previous baby with neonatal GBS infection
  • GBS isolated in current pregnancy on genital tract swab or MSSU

These women should be counselled appropriately antenatally and be given an information sheet to enable them to make a decision regarding antibiotics in labour. Their decision regarding the use of intrapartum antibiotics should be clearly documented in the case notes. Under normal circumstances, this should not be something that is discussed after the onset of labour.

If the woman would like to receive antibiotics these should be given as soon after the onset of labour as possible. Clearly there are occasions when the onset of labour is difficult to establish, thus the following guidelines should cover most situations:

  • If in established labour, give antibiotics (as per protocol below) until delivery.
  • If not in established labour and membranes intact, no need for antibiotics until either membranes rupture or contractions become more regular with resultant cervical dilatation.
  • If labour being induced with prostaglandins, antibiotics should not be given until either membranes rupture spontaneously, artificially or labour is established.
  • If labour is induced by ARM (+/- oxytocin) antibiotics should be given prior to ARM.
  • If delivered by elective LSCS prior to the onset of labour, the usual antibiotic prophylaxis should be administered and no additional antibiotics are required to cover GBS.

Prelabour rupture of membranes (PROM)

Previous Identified GBS Carriers
There is no indication to offer intrapartum prophylaxis to women who were found to be carriers for GBS in a previous pregnancy. The labour should be managed as usual and there is no need for an extended period of neonatal observation so early discharge could still be offered if appropriate.

Occasionally women who have had GBS in a previous pregnancy will enquire about prophylaxis and screening. The likelihood of carriage in a subsequent pregnancy is around 38% and would give a risk of neonatal GBS disease of approximately 0.9 cases per 1000 births, approx double the background risk.  If a previous carrier requests prophylaxis in the current pregnancy, it is reasonable to offer screening at 36 weeks to inform the need for intrapartum prophylaxis. This is in the form of a low vaginal swab which can be obtained by the midwife or self taken. The results should be clearly documented in the handheld notes. This is preferable to advising intrapartum prophylaxis on the basis of past history without knowing the current GBS status.

This discussion should occur in the antenatal period and be documented in the handheld notes. Women should be given the patient information leaflet supplied by the GBS support group which confirms this advice. 

4.2.1 Intrapartum Antibiotic Regime

Procedure or situation

Prophylaxis recommended?

Evidence level

Aim of prophylaxis

Antimicrobial dose/route
Give <1 hour before procedure starts unless otherwise stated


MRSA risk (GL1453)

True Penicillin Allergy

Genital tract colonisation or infection with GBS this pregnancy (MSU or HVS) OR previously infected baby



To reduce early onset neonatal GBS infection

Benzyl penicillin electronic Medicines Compendium information on Benzyl penicillin IV 3g at onset of labour or rupture of membranes. Followed by Benzyl penicillin electronic Medicines Compendium information on Benzyl penicillin IV 1.8g every 4 hours until delivery


Clindamycin electronic Medicines Compendium information on Clindamycin  IV 600mg at onset of labour or rupture of membranes, followed by 600mg every 6 hours until delivery.

See Antimicrobial Prophylaxis in Labour Guidelines

  • Women who are already receiving intravenous antibiotics for other reasons do not need penicillin in addition to these antibiotics if the antibiotic used covers GBS (e.g. amoxicillin, cefuroxime).

4.2.2 Antenatal or Intrapartum Monitoring
Women who receive antibiotics only for intrapartum prophylaxis but are otherwise low risk, do not need to have an admission CTG or continuous fetal monitoring in labour.

4.3 Postnatal Care

4.3.1 Maternal
Women who received antibiotics only for intrapartum prophylaxis do not need to continue to receive antibiotics after delivery.  They are not suitable for early discharge as the baby will need observations for 24 hours. It is imperative that the neonatologists are informed if a woman is a GBS carrier so that appropriate neonatal observations, investigations and, where necessary treatment can be instituted.

4.3.2 Neonatal care

Adequate intrapartum prophylaxis is when a baby is born 4 hours or more after the mother received her first dose of Benzyl penicillin electronic Medicines Compendium information on Benzyl penicillin or Clindamycin electronic Medicines Compendium information on Clindamycin.

Inadequate intrapartum prophylaxis is when the baby is born within 4 hours of the first dose of antibiotics meaning the infant will need further treatment.

Details regarding management of the neonate can be found in “Guideline for post partum management (including antimicrobial prophylaxis) of new-born babies with risk factors for sepsis including (group B streptococcal (GBS) sepsis and prolonged rupture of the membranes) See Sepsis - Antibiotics for Early Onset Sepsis in the Newborn for more information

All neonatal observations should be documented on the Newborn Observation Chart

4.4 What needs to be done if a GBS positive result is found postnatally and the mother and baby have been discharged?

If maternal colonization with GBS is identified within 72 hours of birth, and the woman is still in hospital, the relevant clinical area will be notified of the result.

If the birth was more than 72 hours previously and the baby is at home, the woman should have already received information regarding monitoring her baby’s health in the early weeks of life and no additional action is required. However, the information may be important if her baby does become unwell.

As such, positive results will be forwarded to the screening midwives who will send the woman and her GP a letter which will inform her that she is a carrier for GBS.

This is of no significance at this point for her or the baby as GBS infections passed from mother to baby present within the first 24-48 hours of life. However, as a precaution, she should mention the presence of the organism if the baby becomes unwell or is seen at the hospital within the first few weeks of life.

Back to top

Appendix 1 - Flowchart for care of women at risk of neonatal GBS infection

Summary of Management of Group B Streptococcus Colonisation in Pregnancy

Back to top

Appendix 2 - Indication for intra-partum antibiotics

The Royal College of Obstetricians and Gynaecologists (RCOG) recommends the use of intrapartum antibiotic prophylaxis (IAP) in women who are at increased risk of exposing their baby to maternal GBS around the time of birth, with at least one of the following risk factors:3,4

  • Previous baby with invasive GBS infection (GBS-specific IAP)
  • GBS bacteriuria in the current pregnancy (GBS-specific IAP)
  • Vaginal swab positive for GBS in current pregnancy (GBS-specific IAP)
  • Pyrexia (above 38 °C) in labour (broad-spectrum IAP with GBS cover)
  • Chorioamnionitis (broad-spectrum IAP with GBS cover).

IAP for GBS is not necessary if delivering by pre-labour lower segment caesarean section with intact membranes.

Back to top

Appendix 3 - Newborn Observation Chart

Back to top


Record: 2865

To prevent early onset Group B Streptococcal Neonatal Infection

Clinical condition:

Early onset neonatal GBS

Target patient group: All pregnant women diagnosed with Group B Streptococcus carriage/ infection
Target professional group(s): Secondary Care Doctors
Adapted from:

Evidence base

  1. Prevention of early onset neonatal group B Streptococcal disease. RCOG Guideline No. 36, November 2003.
  2. Anthony BF, Okada DM, Hobel CJ. Epidemiology of group B Streptococcus: longitudinal observations during pregnancy. J Infect Dis 1978;137:524-30.
  3. Regan JA, Klebanoff MA, Nugent RP, Vaginal infections and prematurity study group. The epidemiology of group B streptococcal colonization in pregnancy. Obstet Gynecol 1991;77:604-10.
  4. Dillon HC, Gray E, Pass MA, Gray BM. Anorectal and vaginal carriage of group B streptococci during pregnancy. J Infect Dis 1982;145:794-9.
  5. Boyer KM, Gadzala CA, Kelly PD, Burd LI, Gotoff SP. Selective intrapartum chemoprophylaxis of neonatal group B streptococcal early-onset disease. II. Predictive value of prenatal cultures. J Infect Dis 1983;148:802-9.
  6. Baker CJ, Edwards MS. Group B streptococcal infections. In: Remington J, Klein JO, eds. Infectious diseases of the fetus and newborn infant. 4th ed. Philadelphia: WB Saunders, 1995:980-1054.
  7. Gardner SE, Yow MD, Leeds LJ, Thompson PK, Mason EO, Clark DJ. Failure of penicillin to eradicate group B streptococcal colonization in the pregnant woman: a couple study. Am J Obstet Gynecol 1979;135:1062-5.
  8. Yow MD, Mason EO, Leeds LJ, Thompson PK, Clark DJ, Gardner SE. Ampicillin prevents intrapartum transmission of group B streptococcus. JAMA 1979;241:1245-7.
  9. Easmon CSF, Hastings MJG, Deeley J, Bloxham B, Rivers RPA, Marwood R. The effect of intrapartum chemoprophylaxis on the vertical transmission of group B streptococci. Br J Obstet Gynaecol 1983;90:633-5.
  10. Boyer KM, Gadzala CA, Kelly PD, Gotoff SP. Selective intrapartum chemoprophylaxis of neonatal group B streptococcal early-onset disease. III. Interruption of mother-to-infant transmission. J Infect Dis 1983;148:810-6.
  11. Matorras R, Garcia-Perea A, Omenaca F, Diez-Enciso M, Madero R, Usandizaga JA. Intrapartum chemoprophylaxis of early-onset group B streptococcal disease. Eur J Obstet Gynecol Reprod Biol 1991;40:57-62.
  12. Lim DV, Morales WJ, Walsh AF, Kazanis D. Reduction of morbidity and mortality rates for neonatal group B streptococcal disease through early diagnosis and chemoprophylaxis. J Clin Microbiol 1986;23:489-92.
  13. Allardice JG, Baskett TF, Seshia MMK, Bowman N, Malazdrewicz R. Perinatal group B streptococcal colonization and infection. Am J Obstet Gynecol 1982;142:617-20.
  14. Garland SM, Fliegner JR. Group B streptococcus and neonatal infections: the case for intrapartum chemoprophylaxis. Aust N Z J Obstet Gynaecol 1991;31:119-22.
  15. Boyer KM, Gotoff SP. Prevention of early-onset neonatal group B streptococcal disease with selective intrapartum chemoprophylaxis. N Engl J Med 1986;314:1665-9
  16. NICE (2003) Antenatal care: Routine Care for Health Pregnant Women, National Institute for Clinical Excellence, RCOG Press

Back to top

Approved By

Trust Clinical Guidelines Group

Document history

LHP version 1.0

Related information

Not supplied

Equity and Diversity

The Leeds Teaching Hospitals NHS Trust is committed to ensuring that the way that we provide services and the way we recruit and treat staff reflects individual needs, promotes equality and does not discriminate unfairly against any particular individual or group.