Overview
Uterine Rupture
1. Clinical Overview
Summary
Uterine rupture is a life-threatening obstetric emergency involving a full-thickness tear of the uterine wall. It most commonly occurs during trial of labour after caesarean section (TOLAC) at the previous scar site. Rapid recognition and emergency surgery are essential to prevent maternal and fetal death.
Key Facts
| Aspect | Detail |
|---|---|
| Incidence | 0.5% in VBAC (lower segment scar); 4-9% classical scar |
| Most Common Cause | Dehiscence of previous caesarean scar |
| First Sign (often) | Fetal bradycardia on CTG |
| Treatment | Emergency laparotomy |
Clinical Pearls
- CTG changes precede symptoms: Persistent fetal bradycardia may be the ONLY warning sign
- "Baby floats up": Loss of station/presenting part is pathognomonic
- Contractions cease: May stop suddenly after rupture
- Classical scar = higher risk: 4-9% rupture rate vs 0.5% for lower segment
2. Epidemiology
Incidence by Scenario
| Scenario | Risk of Rupture |
|---|---|
| VBAC (lower segment scar) | 0.5% (1 in 200) |
| Classical caesarean scar | 4-9% |
| Unscarred uterus | Very rare (1:8000-15000) |
| Induction with prostaglandins (scarred) | 2.5x increased risk |
Risk Factors
| Risk Factor | Mechanism |
|---|---|
| Previous caesarean section | Scar weakness |
| Classical/T-incision | Weaker scar |
| Short inter-delivery interval (<18 months) | Incomplete healing |
| Induction/augmentation | Increased uterine activity |
| Multiple previous caesareans | Cumulative scar thinning |
| Uterine surgery | Myomectomy, perforation |
| Grand multiparity | Thin myometrium |
| Malpresentation | Obstructed labour |
3. Pathophysiology
Types of Rupture
| Type | Features |
|---|---|
| Complete (true) rupture | Full thickness tear through myometrium + serosa |
| Incomplete (dehiscence) | Separation of scar with intact serosa |
Mechanism
Previous Caesarean Scar (area of weakness)
↓
Labour Contractions (especially augmented)
↓
Increasing Stress on Scar
↓
Scar Dehiscence → Full Rupture
↓
┌─────────────────────────────────┐
↓ ↓
Fetal Extrusion Maternal Haemorrhage
into Peritoneum (can be massive)
↓ ↓
Fetal Hypoxia/Death Maternal Shock/Death
4. Clinical Presentation
Warning Signs (in order of frequency)
| Sign | Notes |
|---|---|
| Fetal heart abnormalities | Bradycardia, late decelerations - MOST COMMON |
| Abdominal pain | Severe, continuous (not just contractions) |
| Pain between contractions | Scar tenderness may precede |
| Cessation of contractions | Uterus stops contracting |
| Vaginal bleeding | Variable, may be concealed |
| Maternal tachycardia | Compensation for blood loss |
| Hypotension/shock | Late sign |
| "Baby floats up" | Loss of station |
| Change in uterine shape | Visible/palpable change |
Classic Triad (not always present)
- Fetal distress
- Severe abdominal pain
- Vaginal bleeding
5. Clinical Examination
Maternal Assessment
| Finding | Significance |
|---|---|
| Tachycardia | Blood loss compensation |
| Hypotension | Significant haemorrhage |
| Abdominal tenderness | Localised or generalised |
| Scar tenderness | May indicate impending rupture |
| Abnormal uterine contour | Fetal parts may be palpable |
Fetal Assessment
| Finding | Significance |
|---|---|
| CTG bradycardia | Most common first sign |
| Loss of presenting part | Baby extruded into abdomen |
| Absent fetal heart | Fetal death |
6. Investigations
Diagnosis
- Clinical diagnosis - no time for investigations in acute setting
- Emergency laparotomy is both diagnostic and therapeutic
Pre-labour Assessment (planned VBAC)
| Assessment | Purpose |
|---|---|
| Previous operative notes | Scar type, complications |
| Ultrasound | Scar thickness (controversial predictive value) |
7. Management
Emergency Management Algorithm
SUSPECTED UTERINE RUPTURE
↓
Call for Help (Obstetric Emergency Team)
↓
Simultaneous Actions:
• Stop oxytocin/prostaglandins
• IV access (2 large bore)
• Cross-match 4-6 units
• Activate massive transfusion if needed
• Emergency buzzer
↓
CATEGORY 1 CAESAREAN (Decision to Delivery <30 min)
↓
↓
LAPAROTOMY
↓
Assess Uterus
↓
┌──────┴──────┐
↓ ↓
Repairable Not Repairable /
Uncontrollable Bleeding
↓ ↓
Repair of HYSTERECTOMY
Rupture (subtotal or total)
Resuscitation
| Component | Action |
|---|---|
| Airway/Breathing | High-flow oxygen |
| Circulation | IV fluids, blood transfusion |
| Massive transfusion | If needed (1:1:1 ratio) |
| TXA | Tranexamic acid 1g IV |
Surgical Options
| Option | Indication |
|---|---|
| Primary repair | Small tear, good tissue quality |
| Hysterectomy | Uncontrollable haemorrhage, extensive damage |
Neonatal Care
- Neonatal team present at delivery
- Immediate resuscitation likely needed
- High risk of HIE if delayed delivery
8. Complications
Maternal Complications
| Complication | Notes |
|---|---|
| Haemorrhagic shock | Life-threatening |
| Hysterectomy | May be necessary |
| Bladder injury | If rupture extends anteriorly |
| Maternal death | 1% of complete ruptures |
| Future pregnancy risk | Repeat rupture risk |
Fetal Complications
| Complication | Notes |
|---|---|
| Hypoxic ischaemic encephalopathy | Delayed delivery |
| Fetal death | 6% of complete ruptures |
9. Prognosis & Outcomes
| Factor | Outcome |
|---|---|
| Prompt diagnosis/treatment | Good maternal outcome |
| Decision-to-delivery time | Critical for fetal outcome |
| Complete vs incomplete | Complete worse prognosis |
| Maternal mortality | ~1% (complete rupture) |
| Fetal mortality | ~6% (complete rupture) |
Future Pregnancies
- Elective caesarean section recommended
- Short inter-pregnancy interval contraindicated
10. Evidence & Guidelines
| Organisation | Key Points |
|---|---|
| RCOG Green-top 45 | VBAC management, risk stratification |
| NICE Caesarean section | Counselling for TOLAC |
| ACOG | Recommendations for TOLAC |
Induction in Scarred Uterus
- Prostaglandins: 2.5x increased rupture risk
- Oxytocin: Modest increase (use cautiously)
- Mechanical (balloon) + oxytocin: May be safer
11. Patient / Layperson Explanation
What is uterine rupture? It is a rare but very serious emergency where the wall of the womb (uterus) tears during labour, usually at the site of a previous caesarean section scar.
Who is at risk? Women who have had a previous caesarean section attempting vaginal birth are at highest risk. The risk is about 1 in 200 with a low transverse scar.
What are the warning signs?
- Baby's heart rate dropping suddenly
- Severe tummy pain that doesn't ease between contractions
- Heavy vaginal bleeding
- Feeling unwell or faint
What happens if it occurs? Emergency surgery is needed immediately. The baby needs to be delivered by caesarean section as quickly as possible, and the tear in the womb is repaired. Sometimes the womb needs to be removed.
Can I still have a vaginal birth after caesarean? Yes, for many women VBAC is safe and successful (70-75% success rate). You should discuss your individual risk with your obstetrician.
12. References
- RCOG Green-top Guideline No. 45: Birth After Previous Caesarean. 2015.
- NICE NG192. Caesarean Section. 2021.
- Landon MB, et al. Maternal and perinatal outcomes with rupture of uterus. AJOG. 2004.