Preterm Labour and Birth (NICE NG25)

/ Green-top 2011, Green-top guidelines, Management of Labour & Post-partum problems / By

Preterm Labour and Birth (NICE NG25)

Overview

This guideline addresses the care of women at risk of, or experiencing, preterm labour before 37 weeks of gestation. It aims to improve maternal and neonatal outcomes through evidence-based recommendations for diagnosis, prevention, and management.

Who is it for?

  • Healthcare professionals
  • Women at risk of or experiencing preterm labour
  • Families, carers, and the public

Information and Support

Providing Information

  • Offer oral and written information on preterm labour and birth.
  • Include details on:
    • Symptoms of preterm labour
    • Possible treatments (progesterone, cervical cerclage, tocolysis)
    • Neonatal care
    • Short-term and long-term outcomes for preterm babies
    • Possible complications

Support Considerations

  • Address anxiety and provide psychological support.
  • Offer tours of neonatal units and discussions with neonatologists.
  • Tailor information for women from minority ethnic backgrounds or deprived areas due to higher risks of adverse outcomes.
  • Provide ongoing opportunities to discuss resuscitation options and parental preferences.

Care of Women at Risk of Preterm Labour

Risk Factors

  • Previous spontaneous preterm birth or late miscarriage
  • Cervical trauma (e.g., LLETZ or cone biopsy)
  • Short cervix (<25 mm) on ultrasound
  • Preterm prelabour rupture of membranes (P-PROM)
  • Multiple pregnancies
  • Uterine anomalies
  • Smoking and low socioeconomic status

Cervical Length Measurement

  • Use transvaginal ultrasound to measure cervical length between 16+0 and 24+0 weeks in women with risk factors.
  • Short cervix (<25 mm) increases the risk of preterm birth.
  • Repeat measurements every 2-4 weeks if cervical length is borderline (25–30 mm).
Cervical Length Management Notes
≥25 mm No intervention Routine antenatal care
10–24 mm Offer vaginal progesterone Discuss cervical cerclage if history of preterm birth
<10 mm Offer cervical cerclage High risk of preterm birth

Fetal Fibronectin Testing

  • Use fetal fibronectin testing to assess the risk of preterm birth between 22+0 and 34+6 weeks in symptomatic women.
  • A positive result (≥50 ng/mL) indicates an increased risk of preterm birth within 7 days.
  • A negative result (<50 ng/mL) indicates a low likelihood of preterm birth within 7 days.
Fetal Fibronectin Result Management Risk of Delivery
<50 ng/mL Discharge with advice Low
50–199 ng/mL Consider repeat test + observation Moderate
≥200 ng/mL Admit + consider tocolysis + corticosteroids High

Prophylactic Vaginal Progesterone

Indication Dose Duration Evidence Grade
History of spontaneous preterm birth + cervical length ≤25 mm 200 mg vaginal capsules 16+0 to 34+0 weeks Strong evidence
Short cervix (≤25 mm) with no prior history 200 mg vaginal capsules 16+0 to 34+0 weeks Moderate evidence
No short cervix, but history of spontaneous preterm birth Not recommended – Limited evidence

Prophylactic Cervical Cerclage

Indication Timing Risks Notes
Short cervix + History of preterm birth 16+0 to 24+0 weeks Infection, Bleeding Equal option to vaginal progesterone
Short cervix + P-PROM in previous pregnancy 16+0 to 24+0 weeks Infection, Bleeding Discuss risks vs. benefits
Cervical trauma history 16+0 to 24+0 weeks Infection, Bleeding Specialist referral needed

Diagnosing Preterm Prelabour Rupture of Membranes (P-PROM)

Diagnostic Steps

Examination Type Interpretation Next Steps
Speculum Examination Pooling of fluid Diagnose P-PROM
Insulin-like Growth Factor Binding Protein-1 Test Positive Manage as P-PROM
Placental Alpha-Microglobulin-1 Test Positive Manage as P-PROM
Nitrazine Test Not recommended –

Identifying Infection in P-PROM

  • Use C-reactive protein (CRP), white blood cell count, and fetal heart rate monitoring to identify intrauterine infection.
  • Do not rely on single CRP measurements alone.
  • Reassess clinical status regularly.

Antenatal Antibiotics for P-PROM

Antibiotic Dose Duration Notes
Erythromycin 250 mg 4 times/day 10 days or until labour First-line option
Penicillin 500 mg 4 times/day 10 days or until labour Alternative if erythromycin intolerant
Co-amoxiclav Not recommended – Associated with neonatal necrotising enterocolitis

Managing Preterm Labour

Tocolysis

Gestational Age First-Line Second-Line Contraindicated
24+0–33+6 weeks Nifedipine Oxytocin receptor antagonist Betamimetics
<24 weeks Not recommended Not recommended –

Maternal Corticosteroids

Gestational Age Indication Drug Dose Timing
22+0–23+6 weeks High risk of preterm birth Betamethasone or Dexamethasone 2 doses, 12 hours apart Discuss risks vs. benefits
24+0–33+6 weeks Suspected or established preterm labour Betamethasone or Dexamethasone 2 doses, 12 hours apart Standard care
34+0–35+6 weeks Consider Betamethasone or Dexamethasone 2 doses, 12 hours apart Individualised decision

Magnesium Sulfate for Neuroprotection

Gestational Age Dose Duration Notes
23+0–23+6 weeks 4 g IV bolus + 1 g/hour infusion 24 hours or until birth Discuss risks vs. benefits
24+0–29+6 weeks 4 g IV bolus + 1 g/hour infusion 24 hours or until birth Standard care
30+0–33+6 weeks Consider same regime 24 hours or until birth Individualised decision

Fetal Monitoring

Gestational Age Monitoring Method Notes
<26 weeks Intermittent Auscultation Discuss options with the woman
26–33 weeks CTG or Intermittent Auscultation Explain risks and benefits
>34 weeks CTG Standard practice

Mode of Birth

  • Discuss risks and benefits of vaginal vs. caesarean birth.
  • Consider caesarean birth for breech presentation from 26+0 to 36+6 weeks.
  • Avoid fetal scalp electrodes before 34+0 weeks.
  • Explain implications of classical uterine incision for future pregnancies.

Timing of Cord Clamping

  • Wait at least 60 seconds before clamping the cord unless contraindicated.
  • Position the baby at or below the placenta before clamping.

Conclusion

This guideline emphasises individualised care, evidence-based interventions, and multidisciplinary decision-making to optimise maternal and neonatal outcomes in preterm labour and birth. Cervical length measurement, fetal fibronectin testing, and gestational age are key factors in guiding management and improving outcomes. Regular review and shared decision-making remain critical for improving clinical outcomes.

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