NICE NG25: Preterm Labour and Birth

This is the current, actively-maintained NICE guideline on preterm labour and birth. For a general historical overview see rcog-gtg/preterm-labour-overview.md; for cervical cerclage technique and patient-selection detail specifically, see RCOG GTG 75.

Prediction of Preterm Birth

Transvaginal cervical length (TVUS):

• A cervical length of 25 mm or less, measured between 16+0 and 24+0 weeks, identifies women at increased risk of preterm birth.

Diagnosing preterm labour in symptomatic women (intact membranes):

• In women ≥30+0 weeks with symptoms of preterm labour, if cervical length on TVUS is 15 mm or less, regard the woman as being in diagnosed preterm labour.
• Fetal fibronectin testing is used as an adjunct in symptomatic women: a concentration of 50 ng/ml or less suggests a low risk of birth within 48 hours; a concentration of more than 50 ng/ml is treated as diagnostic of preterm labour.

Prevention

Vaginal progesterone:

• Offer to women with a history of spontaneous preterm birth (at or before 34+0 weeks) or a mid-trimester loss (from 16+0 weeks), and a cervical length of 25 mm or less on TVUS performed between 16+0 and 24+0 weeks.
• Start between 16+0 and 24+0 weeks and continue until at least 34 weeks.

Cervical cerclage:

• Offered to women meeting equivalent risk-factor and cervical-length criteria (history of spontaneous preterm birth/mid-trimester loss, or prior P-PROM/cervical trauma, with a short cervix on TVUS in the 16+0–24+0 week window).
• NG25 covers the indication; RCOG GTG 75 is the corpus reference for cerclage technique (history-indicated vs ultrasound-indicated vs rescue), operative detail and removal timing.

Management of Established or Threatened Preterm Labour

Tocolysis:

• 24+0–25+6 weeks, intact membranes: consider nifedipine.
• 26+0–33+6 weeks, intact membranes: offer nifedipine.
• If nifedipine is contraindicated, offer an oxytocin receptor antagonist (atosiban) instead.
• Purpose is to delay birth long enough to complete corticosteroids and, if needed, arrange in-utero transfer — not to prolong pregnancy indefinitely.

Antenatal corticosteroids:

• 22+0–23+6 weeks: discuss with the woman and her family, taking an individualised approach that accounts for survival and morbidity likelihood.
• 24+0–33+6 weeks: offer a course of corticosteroids.
• 34+0–35+6 weeks: consider a course.
• Repeat course: a single repeat course may be considered for women under 34+0 weeks if the first course was given more than 7 days earlier and the woman is judged to be at very high risk of birth within the next 48 hours.
• Do not give more than 2 courses in total.

Magnesium sulphate for fetal neuroprotection:

• 23+0–23+6 weeks: discuss, with an individualised decision.
• 24+0–29+6 weeks: offer, in established preterm labour or where planned preterm birth is anticipated within 24 hours.
• 30+0–33+6 weeks: consider under the same circumstances.
• Dosing: 4 g intravenous bolus over 15 minutes, followed by 1 g/hour by infusion until birth or for 24 hours — whichever is sooner.

High-Yield Exam Points

• Short cervix threshold for offering vaginal progesterone or cerclage: TVUS cervical length ≤25 mm, measured at 16+0–24+0 weeks.
• Diagnostic cervical length cut-off in symptomatic women ≥30+0 weeks: ≤15 mm = diagnosed preterm labour.
• Fetal fibronectin: ≤50 ng/ml = low risk within 48h; >50 ng/ml = treated as diagnostic of preterm labour.
• Nifedipine tocolysis: consider at 24+0–25+6 weeks, offer at 26+0–33+6 weeks; atosiban if nifedipine contraindicated.
• Corticosteroids: offer 24+0–33+6 weeks; discuss at 22+0–23+6 weeks; consider at 34+0–35+6 weeks. Maximum of 2 courses ever, repeat course only if >7 days since the first and very high risk of birth within 48 hours.
• Magnesium sulphate neuroprotection: offer 24+0–29+6 weeks, consider 30+0–33+6 weeks, discuss 23+0–23+6 weeks. Regimen: 4 g IV bolus over 15 minutes, then 1 g/hour until birth or for 24 hours, whichever is sooner.
• This guideline was last formally reviewed in May 2023, with no further update currently planned — treat NG25 thresholds above as the current exam-relevant standard over any older recall figures.

Reference

NICE NG25. Preterm Labour and Birth. National Institute for Health and Care Excellence. Available at: https://www.nice.org.uk/guidance/ng25

Source: National Institute for Health and Care Excellence (NICE) (10 June 2022 (last reviewed 1 May 2023 — no update to recommendations planned unless new evidence emerges))

Read the original on nice.org.uk

Clinically reviewed by NHS obstetricians and gynaecologists · Source last updated 10 June 2022 (last reviewed 1 May 2023 — no update to recommendations planned unless new evidence emerges)

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