Preterm labour

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

Cervical cerclage

Preterm labour management flowchart

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.

Preterm labour management flowchart

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

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.

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 us.

References

• Early onset Group B Streptococcal disease (2010). Queensland Clinical Guideline.
• Measurement of cervical length for prediction of preterm birth (2012). RANZCOG.
• Prelabour rupture of membranes (≥37 weeks) clinical guideline (2015) SA Maternal and Neonatal Clinical Network.
• Preterm labour (2016) KEMH.
• Preterm labour and birth (2014). Queensland Clinical Guidelines.
• The Association Between Pre-pregnancy BMI and Preterm Delivery in a Diverse Southern California Population of Working Women (2011). Maternal & Child Health Journal.
• Antenatal corticosteroids for maturity of term or near term fetuses: systematic review and meta-analysis of randomized controlled trials (2016). BMJ  355 doi.
• Management of Perinatal Infections (2014). Palasanthiran, Starr, Jones & Giles. NSW: Australian Society for Infectious Diseases.