Key messages

  • 'Preterm' refers to a gestational age <37+0 weeks of pregnancy.
  • If a woman presents in preterm labour at a gestation outside the service's Newborn Capability Level, aim for in-utero transfer wherever possible.
  • Be alert for any form of sepsis.
  • The key elements of assessment are clinical examination, including abdominal palpation and speculum examination, ultrasound and pathology testing.
  • The key elements of management are tocolysis, antibiotics, corticosteroids and magnesium sulfate.
  • Ensure the placenta is sent for histopathological examination.

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Preterm labour

In 2013, 7.2 per cent of babies in Victoria were born preterm - at less than 37 weeks gestation. This rate of preterm birth has been stable since 2000 and in 2013 represented approximately 5,600 babies. The majority of these babies were born between 32 and 36 weeks.

Preterm labour and the care of premature babies present a range of challenges for families and health care services. Most importantly, babies born preterm have higher rates of neonatal morbidity and mortality and are at higher risk of neurodevelopmental disorders than babies born at term.

Appropriate management of preterm labour involves timely assessment, with the aim of ensuring birth occurs in the optimal location for the baby. Optimal location of care will depend on a baby's gestation at birth and the required level of nursery care, as per the Newborn Capability Framework.

For assistance with assessment and management, contact PIPER: 1300 137 650.

Risk factors

Risk factors associated with preterm labour and birth
Maternal characteristics
  • <18 years of age
  • >35 years of age
  • Ethnicity:
    • Aboriginal - risk increased by 70%
    • African - risk increased by 60%
    • South Asian - risk increased by 40%
  • Cigarette smoking - risk increased by 30%
  • High levels of psychological stress
  • Late booking or no pregnancy care
  • Low socio-economic status
  • BMI <19
  • BMI >30
Medical and pregnancy conditions
  • Previous preterm birth
  • Short cervical length
  • PPROM
  • Multiple gestation
  • Presence of fetal fibronectin in vaginal secretions
  • Genital tract infections
  • Urinary tract infections
  • Vaginal bleeding
  • Conceived using artificial reproductive technology (ART)
  • Cervical surgical procedures
  • Uterine anomalies
  • Polyhydramnios
  • Oligohydramnios
  • Chronic medical conditions
  • Acute medical conditions (pre-eclampsia, APH)

Prevention

For women with a history of spontaneous preterm birth or an ultrasound diagnosis of shortened cervix, progesterone therapy or cervical cerclage may be appropriate to prevent preterm labour.

Progesterone therapy

Indication Intervention
History of spontaneous preterm birth Commence progesterone 200 mg vaginal suppository daily from 16-24 weeks. Continue until 34 weeks gestation, rupture of membranes or birth, whichever occurs first.
Shortened cervix - singleton gestation
Shortened cervix - multiple gestation No evidence for improving outcomes with progesterone therapy.

Cervical cerclage

Indication Intervention
History of spontaneous preterm birth Offer cervical cerclage
History of cerclage for painless cervical dilation in 2nd trimester
Cervix <25 mm at <24 weeks gestation, with a history of spontaneous preterm birth - singleton
Cervical shortening or painless dilation >24 weeks gestation Limited data to support rescue cerclage - individualise decisions
Cervix <25 mm at <24 weeks gestation, without a history of spontaneous preterm birth - singleton Cerclage not recommended
Funnelling of the cervix in absence of cervical shortening
History of cervical surgeries or anomalies
Multiple pregnancy

Assessment

Preterm labour QRA

Review history

Full obstetric, medical, surgical and social history.

Assess for signs and symptoms of preterm labour

  • Regular uterine activity
  • Lower abdominal cramping
  • Vaginal loss - mucous, blood, fluid, meconium
  • Lower back pain
  • Pelvic pressure
  • Presenting part fixed or engaged

Physical examination

  • Vital signs - heart rate, blood pressure, respiratory rate, oxygen saturation, temperature
  • Abdominal palpation - pain, rigidity, contractions, fetal presentation, size and movement
  • Fetal surveillance - Fetal heart rate (FHR) or cardiotocograph (CTG)

Speculum

  • Sterile speculum examination:
    • visualise the cervix, looking for changes in length and dilatation
    • assess for rupture of membranes.
  • During the speculum examination test for fetal fibronectin* (fFN):
    • perform a quantitative fFN test, if available
    • be aware that the presence of blood or semen in the vagina may affect test reliability but that a negative result is still valid.

* This may not be necessary if in a facility with capability for the gestation. Perform high and low vaginal swabs.

Ultrasound

  • Abdominal ultrasound (US) for fetal growth and wellbeing
  • Transvaginal US for cervical length

Pathology investigations

  • Midstream urine for MCS
  • Full blood examination
  • C-Reactive Protein
  • High vaginal swab
  • Low vaginal/anorectal swab for GBS

Management

Preterm labour QRA

Transfer

If a woman presents in preterm labour at a gestation outside the service's Newborn Capability Level, aim for in-utero transfer wherever possible.

Within Victoria, consult with PIPER for support with assessment and transfer: 1300 137 650.

Tocolysis

  • Nifedipine 20 mg oral
  • If contractions persist after 30 minutes, repeat nifedipine 20 mg oral
  • If contractions persist after a further 30 minutes, repeat nifedipine 20 mg oral
  • Maintenance therapy 20 mg every six hours for 48 hours

Antibiotics

GBS Prophylaxis

  • IV Benzylpenicillin 3g loading dose
    then
  • IV Benzylpenicillin 1.8g every four hours

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

  • IV Cephazolin 2g loading dose
    then
  • IV Cephazolin 1g every eight hours

If the woman has a penicillin allergy with history of anaphylaxis

  • IV Clindamycin 900mg every eight hours

Suspected/diagnosed chorioamnionitis

  • Loading dose Ampicillin or amoxycillin 2 g IV, then 1 g every six hours
    and
  • Gentamicin 5 mg/kg IV daily
    and
  • Metronidazole 500 mg IV every 12 hours

Penicillin allergy/hypersensitivity

  • Lincomycin or clindamycin 600 mg IV every eight hours
    and
  • Gentamicin 5 mg/kg IV daily
    and
  • Metronidazole 500 mg IV every 12 hours

Corticosteroids

If ≤36+6 weeks:

  • Betamethasone 11.4 mg IM

followed by

  • Betamethasone 11.4 mg IM in 24 hours
  • consider second dose at 12 hours if birth likely within 24 hours
  • if risk of preterm birth remains ongoing in seven days, repeat a single dose.

Magnesium sulfate (MgSO4)

If <30 weeks:

  • loading dose MgSO4 4 g IV bolus over 20 minutes
  • maintenance dose MgSO4 1 g/hr IV for 24 hours or until birth - whichever is first.

Prepare for birth

  • Consult with obstetric and paediatric clinicians.
  • Anticipate vaginal birth unless there are fetal or maternal contraindications (see below).
  • Prepare resuscitation equipment appropriate for gestation.
  • Notify SCN/NICU.
  • Counsel woman and family about what to expect in terms of baby's condition and care.
  • Offer tour of SCN/NICU if possible.
  • After birth, ensure the placenta is sent for histopathological examination.

Possible contraindications to vaginal birth, subject to individual assessment

  • Placenta praevia
  • Maternal condition necessitating caesarean section
  • Breech and <32 weeks
  • Multiple pregnancy and <26 weeks

Discharge and follow-up

A baby's need for follow-up care will be dependent upon their individual clinical presentation, gestation at birth and complications experienced during their inpatient care.

Practice points

  • Offer the woman and her family the opportunity to debrief with clinicians involved in their care.
  • If a woman and/or baby has been transferred between services, ensure discharge summaries are sent to the referring service and the woman's GP.
  • When organising follow-up care, aim to connect the woman with clinicians and services close to her home wherever possible.
  • Ensure the woman is aware of any follow-up appointments that have been organised for her and her baby.

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.

Auditable standards:

  • Documentation of risk factors
  • All indicated investigations requested, followed up and acted on
  • fFN result and time to delivery
  • Follow up planning

For further information or assistance with auditing, please contact the Maternity and Newborn Clinical Network: maternityehandbook@dhhs.vic.gov.au.

References