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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.
On this page

    In June 2023, we commenced a project to review and update the Maternity and Neonatal eHandbook guidelines, with a view to targeting completion in 2024. Please be aware that pending this review, some of the current guidelines may be out of date. In the meantime, we recommend that you also refer to more contemporaneous evidence.

    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
    Due for review: June 2022


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