Leaking fluid: rupture of membranes
Obstetrics
Triage, any gestation from viability
The first question
Are the membranes ruptured, and at what gestation?
Two patients: the gestational age and the maternal stability first, then the fetal status.
- 01
Confirm
History of a gush or trickle; sterile speculum with pooling; nitrazine and ferning as support; avoid a digital examination unless in labour.
- 02
Gestation and status
Term or preterm; labour or not; GBS status; fever; fetal heart rate; presentation and cord.
- 03
Plan
Term: offer induction or expectant management for up to 24 hours with GBS considerations. Preterm: admit, steroids, latency antibiotics, surveillance.
Where it is
Each opens the structure on the 3D pelvis.
History that discriminates
- Time, volume, colour, odour
- Contractions
- Fever, offensive discharge
- GBS status
- Fetal movements
- Prior preterm rupture
Examination that discriminates
- Temperature, maternal pulse
- Uterine tenderness
- Sterile speculum: pooling, cord, cervical dilatation by inspection, liquor colour
- Fetal heart rate; presentation (a breech or unengaged head raises prolapse risk)
Investigations
- Nitrazine, ferning, or a placental alpha-microglobulin test
- GBS swab if not done
- CBC if infection is a concern
- Ultrasound for liquor volume and presentation
The differential
| Diagnosis | Favours | Against | Urgency |
|---|---|---|---|
| Rupture of membranes | Pooling, ferning, positive nitrazine, oligohydramnios | No pooling, a dry speculum | urgent |
| Urinary incontinence | With cough or urgency, urine odour, no pooling | Continuous clear loss with pooling | routine |
| Physiological discharge or vaginitis | White or coloured discharge, itch, odour, no pooling | Watery clear fluid | routine |
| Show | Mucousy, blood-stained | Watery | routine |
Pitfalls this pathway refuses
- Digital examination in PPROM
- Missing cord prolapse on the speculum
- Reading ferning alone; cervical mucus ferns too