Objectives

On successfully completing this topic, you will be able to:

• discuss the risk factors for uterine rupture

• recognise a ruptured uterus early

• plan and manage a ruptured uterus.

Introduction

Complete rupture of the uterus can be a life-threatening emergency. Fortunately, however, the condition is rare in modern obstetrics, despite the increase in CS rates, and serious sequelae are even more rare.

Incidence and predisposing factors

Population studies, including large numbers (>50 000) of patients over the last few decades, give a low overall incidence of uterine rupture at approximately 0.3/1000 deliveries. Rupture is more likely in multigravid women, especially those who have undergone previous CS, but spontaneous rupture of the unscarred uterus does occur. Risk factors for rupture of an unscarred uterus include:

1. • grand multiparity

2. • undiagnosed cephalopelvic disproportion or malpresentation

3. • oxytocin administration

4. • macrosomic fetus

5. • placenta percreta

6. • prior uterine surgery

7. • version

8. • uterine abnormalities (e.g. rudimentary horn).

Previous CS

Smith et al. looked at 35 854 women who laboured with a previous CS: 74.2% had a vaginal delivery and the incidence of uterine rupture was 0.35%. The risk was higher among women who had not previously given birth vaginally and those whose labour was induced with prostaglandin. Al Zirqi et al. reviewed 18 794 women who gave birth after a CS in Norway from 1999 to 2005. Compared with elective prelabour CS, the odds ratio for rupture with spontaneous labour was 6.65, and for induced labour 12.6. Induction, using prostaglandins, increased the odds for rupture by 2.72 compared with spontaneous labour.