Uterine rupture

Definition

• Uterine rupture is complete division of all three layers of the uterine wall (endometrium, myometrium, perimetrium); it occurs in late pregnancy before or during labour.
• In dehiscence the wall is only incompletely divided, sometimes with a window through which the fetus can be seen; it is often an occult finding without symptoms.

Classification

Special forms

• Dehiscence of an old scar differs from complete rupture in that serosa intact, fetus in uterine cavity.

Occurrence & epidemiology

Epidemiology

• Uterine rupture is rare and occurs most often along a healed scar after previous caesarean section; it can, however, also occur in an unscarred uterus.

Aetiopathogenesis

Risk situation

• The rupture risk after one caesarean is approx. 0.5–1%.
• An epidural is allowed, but can mask the typical pain.

Risk constellations

• Remember: rupture is not confined to labour and can present as an acute abdomen outside contractions.

Aetiology and risk factors

• Further causes are uterine overdistension (multiple pregnancy, polyhydramnios, fetal anomalies), external or internal version, iatrogenic perforation, excessive use of uterotonics and unrecognised dystocia with strong contractions against a lower-segment restriction ring.

Clinical features

Signs

• The Bandl ring is a groove between corpus & lower segment.
• Often the CTG is the first sign — typically variable decelerations, prolonged bradycardia.
• Another sign is the ascent of the presenting part.

Signs

• Sudden severe pain and restlessness, a rising Bandl ring, cessation of contractions, vaginal bleeding, pathological CTG, circulatory instability.
• The Bandl ring is a visible and palpable constriction between the corpus and the overstretched lower segment.
• Another sign: the presenting part rises again as the baby passes into the abdominal cavity.

Clinical features and complications

• Signs are fetal bradycardia, variable decelerations, signs of hypovolaemia, loss of fetal station and severe or constant abdominal pain; the uterus may be atonic or abnormally shaped and tender.
• Vaginal bleeding may be slight despite major intra-abdominal haemorrhage; complications are maternal haemorrhage and bladder injury, and if the fetus lies in the peritoneal cavity, maternal and fetal morbidity and mortality rise considerably.

Diagnosis

• The working diagnosis is clinical, based on risk factors and examination findings; ultrasound cannot reliably distinguish rupture from placental abruption.
• Uterine rupture is confirmed at laparotomy.

Keep learning in the app

Further reading (selection)

1. StatPearls: Uterine Rupture (NCBI Bookshelf)
2. MSD Manual Professional Edition: Uterine Rupture
3. MSD Manual Professional Edition: Vaginal Bleeding During Late Pregnancy
4. DocCheck Flexikon, Uterusruptur
5. DocCheck Flexikon, Bandl-Furche

Cross-references