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Key messages

  • Maternal streptococcus agalactiae, or Group B streptococcus (GBS) colonisation, can lead to early onset sepsis (EOS) infection in the baby and associated morbidity.
  • Identifying women who are at risk of having a baby with GBS enables treatment to be given during labour to reduce the risk of transmission of infection to the baby.
  • There is limited high quality scientific evidence and a lack of expert consensus on whether a risk based or a universal screening approach should be used.
  • Intrapartum antibiotic prophylaxis (IAP) to women at risk of transmitting GBS to their baby, is associated with a reduction in (but does not eliminate) EOS. However it does not prevent late onset sepsis (LOS).
  • Treat all unwell babies for suspected sepsis, irrespective of maternal GBS status or adequate IAP.
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    Introduction - definition

    Group B streptococcus (GBS)

    Practice points

    • GBS is a transient bacterium that is commonly found in the gastrointestinal tract, vagina and urethra in 15-25% of pregnant women (asymptomatic carriers of GBS).
    • GBS is transmitted to the baby during birth in approximately 1–2 per 1000 live births and can lead to serious infection in the baby.
    • EOS may result in neonatal morbidity, including respiratory symptoms, pneumonia and sepsis. It can result in death of the baby if not detected and treated early.
    • IAP can prevent EOS in up to 89 per cent of babies of colonised women (Lin et al. 2001; Schrag et al. 2002).
    • A pregnant woman who tests positive for GBS and gets IAP has a one in 4000 chance of delivering a baby who will develop EOS, compared to a one in 200 chance if she does not have IAP (Centers for Disease Control and Prevention 2018).
    • IAP does not prevent late onset sepsis (LOS).
    • The decision to give antibiotic treatment in labour can be determined through:
      • consistent identification of clinical risk factors during pregnancy and labour
      • taking a combined vaginal-rectal swab at 35-37 weeks gestation.
    • Preterm babies are four times more likely to develop EOS than term babies (Kurz and Davis 2015).


    Risk factors

    Table 1. Obstetric risk factors for EOGBS infection

    Preterm labour <37+0 weeks (spontaneous or induced)

    Rupture of membranes (ROM) ≥18 hours prior to birth

    Maternal temperature ≥38 degrees intrapartum or within 24 hours of giving birth

    GBS colonisation in current pregnancy

    GBS bacteriuria in current pregnancy (any colony count)

    Previous baby with invasive GBS infection

    Practice points

    • If any of the above risk factors are identified, IAP is recommended once active labour is identified.
    • Aim for ≥4 hours of IAP coverage prior to birth.
    • Antibiotic prophylaxis is not recommended prior to the onset of labour.

    Antenatal screening

    Practice points

    • Maternity services across Australia use either a clinical risk-based or universal culture-based screening approach to reduce EOS in the baby.
    • There is a lack of consensus and limited high quality evidence regarding a preferred approach.
    • All maternity services should have an established plan for prevention of EOS. Follow organisational protocols and local guidelines.
    • GBS, EOS and IAP should be discussed with the woman during the antenatal period in a manner that supports informed decision making.
    • Clinicians must remain vigilant for signs of EOS as this can occur in a baby of culture-screened GBS negative women.

    Risk-based management

    • Discuss and document risk factors at booking.
    • If the woman had a previous baby with invasive EOS, discuss and document the recommendation for IAP.
    • If tests at any point in pregnancy show GBS colonisation or bacteriuria:
      • discuss results with the woman and document her status as GBS positive
      • discuss and document the recommendation for IAP
      • if GBS colonisation or bacteriuria is found incidentally or by intentional testing earlier in pregnancy, do not repeat investigation in later pregnancy.
    • If other risk factors arise (see Table 1), IAP is recommended once active labour is identified.

    Universal screening

    • Undertake GBS culture based-screening, using combined vaginal-rectal swab at 35–37 weeks gestation if no risk factors or colonisation has been identified prior to this.
    • Inform all women of the testing procedure and implications of results.
    • If testing is carried out, tell the woman her results and document in antenatal records. Ensure that a woman with a positive result understands the importance of relaying this information to the health professionals who care for her in labour.
    • Where universal screening is used, risk factors are still relevant as EOS can occur in culture-screened GBS negative women, so:
      • discuss and document risk factors at booking and plan for care accordingly
      • continue to assess for risk factors, GBS colonisation or bacteriuria arising later in pregnancy.
    • Inform all women that if their screening result is GBS negative, the presence of risk factors will lead to IAP being recommended.

    Specimen collection

    • Swabs may be collected by a clinician or collected by the woman.
    • Use one single dry swab stick:
      • insert into the vaginal introitus
      • then insert into the anus.
    • Place into standard bacterial transport medium.
    • Label specimen clearly with ‘GBS screening in pregnancy’.
    • Request sensitivity screening for women who are allergic to penicillin.


    Intrapartum management

    Identification of risk factors

    Practice points
    • If risk factors (Table 1) are identified on admission or at any point during labour:
      • discuss the recommendation for IAP with the woman
      • indicate the need for IAP on the partogram and in the progress notes/electronic medical record (EMR).
    • Offer IAP to woman with risk factors irrespective of screening result.

    Intrapartum antibiotic prophylaxis

    See – Term PROM eHandbook page

    See – PPROM eHandbook page

    Practice points

    • Recommend IAP to women with identified risk factors when active labour is identified: Intrapartum antibiotic prophylaxis flowchart.
    • Antibiotic prophylaxis is not recommended prior to the onset of active labour.
    • Adequate prophylaxis is considered to be commenced at least four hours prior to birth.
    • Benzylpenicillin is the antibiotic of choice – IV penicillin and ampicillin are equally effective against GBS, but penicillin is preferable due to its narrower spectrum of activity.
    • A GBS positive screening result is not a preclusion to labour in the bath or pool, or birth through water, as long as antibiotic prophylaxis occurs. 

    Antibiotic regimen

    • IV Benzylpenicillin 3 g loading dose


    • IV Benzylpenicillin 1.8 g every four hours until birth.

    If the woman has a penicillin hypersensitivity with no history of anaphylaxis

    • IV Cephazolin 2 g loading dose
    • IV Cephazolin 1 g every eight hours until birth.

    If the woman has a penicillin allergy with history of anaphylaxis

    • IV Clindamycin 900 mg every eight hours until birth.
    • If sensitivity is unknown or GBS isolate is resistant to Clindamycin, administer IV Vancomycin 1 g every 12 hours until birth.

    Clinical circumstances where IAP is not required

    • GBS carriage detected in a previous pregnancy (even if GBS status is unknown in the current pregnancy).
    • Elective caesarean section (no labour, no rupture of membranes) irrespective of GBS carriage or gestational age.
    • For women where routine surgical antibiotic prophylaxis for CS is indicated.
    • Threatened preterm labour with intact membranes, where the risk of imminent birth is low.

    Postnatal management

    Neonatal care

    Practice points

    • GBS is the most frequent cause of early onset neonatal sepsis in developed countries.
    • Signs of EOS are non-specific and can include respiratory distress, temperature instability, tachycardia, shock, or ‘unwell’  and most likely to arise within 24 hours of birth.
    • Treat all unwell babies for suspected sepsis, irrespective of maternal GBS status or adequate IAP.

    Observation and management

    Follow up and documentation

    Advice for future pregnancy

    Advise the woman that:

    • if she has GBS colonisation in this pregnancy but without infection in the baby, pregnancy and birth management is not affected in her next pregnancy
    • if her baby has been diagnosed with EOS:
      • IAP is recommended during her  next labour
      • her next baby has an increased risk of EOGBS disease and will most likely be offered antibiotic prophylaxis
      • she is able to discuss the impact on future pregnancies with the paediatric/neonatal team
      • she should inform future care providers that she has had a baby with EOS.

    More information

    Audit and performance improvement

    All maternity services should have processes in place for:

    • auditing clinical practice and outcomes
    • providing feedback to clinicians on audit results
    • addressing risks, if identified
    • implementing change, if indicated.

    Potential auditable standards include:

    • adherence to standards of care
    • GBS screening rates.


    • Centers for Disease Control and Prevention (CDC) 2018, ‘Preventing early-onset group B strep disease’, [Internet : viewed May 2019],
    • Kurz, E and Davis, D 2015, ‘Routine culture based screening versus risk based management for the prevention of early onset group B streptococcus disease in the neonate : a systematic review’, Joanna Briggs Institute Database of Systematic Review & Implementation Reports, vol. 13, no. 3, pp. 206-46. DOI: 10.11124/jbisrir-2015-1876.
    • Lin FY, Brenner RA, Johnson YR, Azimi PH, Philips JB 3rd, Regan JA, Clark P, Weisman LE, Rhoads GG, King F &Clemens JD 2001, ‘The effectiveness of risk-based intrapartum chemoprophylaxis for the prevention of early-onset neonatal group B streptococcal disease’. American Journal of Obstetrics and Gynaecology 1, vol. 184, no. 6, pp. 1204-10, DOI: 10.1067/mob.2001.113875.
    • Schrag SJ, Zell ER, Lynfield R, Roome A, Arnold KE, Craig AS, Harrison LH, Reingold A, Stefonek K, Smith G, Gamble M, Schuchat A; for the Active Bacterial Core Surveillance Team 2002. ‘A population-based comparison of strategies to prevent early-onset group B streptococcal disease in neonates’, New England Journal of Medicine, vol. 347, no. 4, pp. 233–39, DOI: 10.1056/NEJMoa020205.


    • American College of Obstetricians and Gynecologists 2011, ‘Prevention of early-onset group B streptococcal disease in newborns’, Obstetrics Gynecology, Committee Opinion No. 485. vol. 117, pp.1019-27.
    • Australasian Society for Infectious Diseases 2014, ‘Management of perinatal infections’, [Internet: viewed May 2019]. available from:
    • Berardi A, Rossi C, Guidotti I, Vellani G, Lugli L, Bacchi Reggiani ML, Ferrari F, Facchinetti F & Ferrari F 2014, ‘Factors associated with intrapartum transmission of group B Streptococcus’, Pediatric Infectious Disease Journal, vol. 33, no. 12, pp. 1211-5, DOI: 10.1097/INF.0000000000000439.
    • Centers for Diseases Control and Prevention 2010, ‘Prevention of perinatal Group B streptococcal disease; revised guidelines’, Morbidity and Mortality Weekly Report, vol. 59, no. RR-10, [Internet: viewed May 2019], available from:
    • Darlow BA, Voss L, Lennon DR & Grimwood K 2016, ‘Early-onset neonatal group B streptococcus sepsis following national risk-based prevention guidelines’, Australian & New Zealand Journal of Obstetrics & Gynaecology, vol. 56, no.1, pp. 69-74. DOI: 10.1111/ajo.12378
    • Department of Health 2018, Clinical Practice Guidelines: Pregnancy Care, Canberra, Australian Government Department of Health, [Internet: viewed May 2019], available from:
    • Hughes RG, Brocklehurst P, Steer PJ, Heath P, Stenson BM on behalf of the Royal College of Obstetricians and Gynaecologists 2017, ‘Prevention of early-onset neonatal group B streptococcal disease. Green-top Guideline No. 36’, British Journal of Gynaecology, vol. 124, no.12, pp. 280-305, DOI: 10.1111/1471-0528.14821.
    • Lin FY, Weisman LE, Troendle J & Adams K 2003, ‘Prematurity is the major risk factor for late-onset group B streptococcus disease’, Journal of Infectious Disease, vol. 188, no. 2, pp. 267-71.
    • Ohlsson A & Shah V 2014, ‘Intrapartum antibiotics for known maternal group B streptococcal colonization’, Cochrane Database of Systematic Reviews, Issue 6,  Art. No. CD007467 DOI:10.1002/14651858.CD007467 pub4.
    • Perinatal Clinical Practice Guidelines Working Party 2010, Clinical Practice Guideline - Prevention of neonatal early onset group B streptococcal disease. Brisbane: Queensland Health, [Internet: viewed May 2019], available from:
    • Royal Women’s Hospital 2018, Clinical Guideline: GBS Colonisation: Management of Infant to Prevent Early Onset Group B Streptococcus (EOGBS) Disease, [Internet: viewed May 2019], from:
    • Turrentine MA, Greisinger AJ, Brown KS, Wehmanen OA, Mouzoon ME 2013, ‘Duration of intrapartum antibiotics for group B streptococcus on the diagnosis of clinical neonatal sepsis’, Infectious Diseases in Obstetrics and Gynecology. Vol. 2013, Art. No. 525878,  DOI:10.1155/2013/525878.
    • Wojcieszek AM, Stock OM, Flenady V 2014, ‘Antibiotics for prelabour rupture of membranes at or near term’, Cochrane Database of Systematic Reviews, Issue 10, Art. No. CD001807, DOI: 10.1002/14651858.CD001807.pub2. 2014
    • World Health Organization 2015, WHO recommendations for prevention and treatment of maternal peripartum infections, [Internet: viewed May 2019], available from:

    Get in touch

    Centre of Clinical Excellence - Women and Children
    Safer Care Victoria

    Version history

    First published: June 2019

    Last web update: June 2019

    Review by: TBC

    Uncontrolled when downloaded

    Page last updated: 24 May 2022

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