Preterm Labour & PPROM — Prevention, Diagnosis & Management
Preterm birth = birth before 37 completed weeks: extremely preterm (< 28 wk), very preterm (28 to < 32 wk), moderate-to-late preterm (32 to < 37 wk)
Preterm labour = regular contractions with cervical change before 37 weeks — contractions alone, without cervical change, are not enough
PROM = rupture of membranes before labour starts, at any gestation; PPROM = PROM before 37 weeks; previable PPROM = before about 24 weeks
About 10% of births are preterm, and prematurity is the leading cause of newborn death; PPROM complicates 2–3% of pregnancies and precedes about one-third of preterm births
Previous spontaneous preterm birth or second-trimester loss
Short cervix, cervical surgery (LEEP or cone)
Multiple pregnancy, polyhydramnios, uterine anomaly
Infection: bacterial vaginosis, UTI, periodontal disease
Bleeding, smoking, low BMI, short interpregnancy interval
Transvaginal cervical length: ≤ 25 mm before 24 weeks is short
Fetal fibronectin (fFN) in symptomatic women with cervical length 15–30 mm — its strength is the negative result
Placental alpha-microglobulin-1 (PAMG-1) tests are an alternative
Combine tests with history — no single test is perfect
Short cervix (≤ 25 mm, before 24 weeks), singleton, no prior preterm birth: vaginal progesterone (200 mg pessary or 90 mg gel nightly) from the time of diagnosis to about 34–36 weeks
Prior spontaneous preterm birth before 34 weeks: serial cervical length from 16–24 weeks; vaginal progesterone; and cerclage if cervical length falls below 25 mm
History-indicated cerclage at 12–14 weeks: three or more preterm births or second-trimester losses, or painless cervical dilatation in a prior pregnancy
Physical-exam cerclage for painless dilatation of the cervix at 16–24 weeks without labour or infection
Screen and treat asymptomatic bacteriuria; stop smoking; treat symptomatic infections; do not use bed rest or routine pessaries
Treat as true preterm labour if cervical dilatation is ≥ 3 cm, or the cervix is shortening or contractions are persistent with a short cervix (< 15 mm)
| Drug | Typical regimen | Key points |
|---|---|---|
| Nifedipine | 20 mg oral stat, then 10–20 mg every 6–8 h for up to 48 h | First choice (NICE); watch for hypotension and headache |
| Atosiban | 6.75 mg IV bolus, then 300 ┬╡g/min for 3 h, then 100 ┬╡g/min up to 45 h | Oxytocin-receptor antagonist; few maternal side effects |
| Indomethacin | 50–100 mg loading, then 25 mg every 4–6 h for up to 48 h | Only before 32 weeks; risks premature ductus closure and oligohydramnios |
| Beta-agonists | Terbutaline, ritodrine | Not recommended — serious maternal risks (pulmonary oedema, arrhythmia) |
Do not use tocolysis with chorioamnionitis, placental abruption, severe pre-eclampsia, fetal death or lethal anomaly, or a non-reassuring fetal state
No maintenance tocolysis after the first 48 hours — it does not improve outcomes
Sterile speculum: pooling of amniotic fluid in the posterior fornix, or fluid leaking on coughing
Nitrazine (turns blue above pH 6.5) and ferning — useful, but blood, semen, urine and bacterial vaginosis cause false positives
Biochemical tests if doubt remains: PAMG-1 (AmniSure) or IGFBP-1 (Actim PROM) — more specific, and not affected by blood
Ultrasound: low amniotic fluid index supports the diagnosis and gives a prognosis; also check presentation and growth
Avoid digital examination unless she is in labour — it shortens the latent period and raises infection risk
| Gestation | Approach |
|---|---|
| Previable (< 24 wk) | Counsel with obstetric and neonatal experts on outcomes; options are expectant management or termination; antibiotics for latency; steroids and magnesium only if viable |
| 24 to < 34 wk | Expectant care in hospital with antibiotics, steroids, magnesium sulphate if before 32 weeks; deliver for infection, abruption, labour, or fetal compromise |
| 34+0 to 36+6 wk | Delivery is recommended (ACOG; RCOG discusses timing) — benefits of delivery outweigh waiting; GBS prophylaxis |
| ≥ 37 wk (term PROM) | Induce labour promptly; expectant management for up to 24 h is acceptable if well; antibiotics if GBS positive or prolonged rupture |
Latency antibiotics lengthen the time to delivery and reduce infection: ACOG — ampicillin 2 g IV every 6 h with erythromycin 250 mg IV every 6 h for 48 h, then amoxicillin with erythromycin by mouth to complete 7 days; RCOG — erythromycin 250 mg four times daily for up to 10 days
Avoid co-amoxiclav — it is linked to necrotising enterocolitis in the newborn
Antenatal corticosteroids at 24–34 weeks, and magnesium sulphate if delivery is expected before 32 weeks
Surveillance: temperature and pulse at least four times daily, uterine tenderness, discharge, CTG, and growth and fluid scans; CRP and white cell count — remember steroids raise WBC for several days
Tocolysis is not routine in PPROM — consider only for 48 hours if she is contracting, to allow steroids to work
Group B streptococcus: test on admission and give prophylaxis in labour unless the culture is negative
Cerclage in situ: removal after PPROM is individualised — remove it for labour, infection or bleeding; otherwise decide with a senior
Chorioamnionitis and postpartum endometritis
Placental abruption (about 4–7% in PPROM)
Sepsis and retained placenta
Prematurity: respiratory distress, IVH, NEC, sepsis, and cerebral palsy
Cord prolapse with malpresentation — see our Cord Prolapse guide
Pulmonary hypoplasia and limb contractures after prolonged rupture before 24 weeks
Tell the family honestly what to expect at this gestation, with the neonatologist if possible
Explain warning signs for those managed as outpatients: fever, leaking, bleeding, contractions, reduced fetal movement
Recurrence risk is high: plan the next pregnancy with cervical length surveillance, progesterone or cerclage, and early booking
Support for postnatal grief and anxiety; lactation support for mothers of preterm babies
Counsel on interpregnancy interval (at least 18 months)
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