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:
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%.1 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 2005.2 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.
NICE recommendation
The NICE induction of labour guideline recommends that the induction of women with a previous CS is reasonable, and that prostin is appropriate, but that it should not occur on antenatal wards.
Hospital units need to provide:
local guidelines regarding the augmentation of labour and induction of labour
local guidelines regarding intrapartum fetal and maternal surveillance in women with a uterine scar.
Perinatal morbidity and mortality from uterine rupture
Leung et al. undertook a retrospective review of 106 cases of uterine rupture.3,4 They found perinatal mortality and morbidity to be associated with complete fetal extrusion and more than 18 minutes delay between the onset of prolonged decelerations and delivery.
CESDI data
In the 1995 CESDI report of intrapartum deaths, there were 12 cases of ruptured uterus.5 The two clinical features that stood out were:
delay in making the diagnosis – fetal distress was invariably present but no action was taken
the use of prostaglandins to induce labour.
Following this, a focus group was set up to review cases of ruptured uterus that were reported in the fifth CESDI report (1998).6 Forty-two cases of ruptured uterus with fetal death were found, 75% of which were considered to have had significantly substandard care and 18 were only diagnosed at laparotomy.
Factors identified in the CESDI report
Obesity (46% BMI greater than 30 compared with 14% of the female population in this age group).
Uterine scar (30/42); of the 12 women without a scar, only one was nulliparous.
Antenatal issues: absence of a recorded plan (five cases), failure to involve seniors (four cases) and inappropriate decision about induction (four cases).
Induction (60%) and augmentation (25%): all 12 women without scars had oxytocics;
23/30 of women with previous CS had oxytocics.
Fifty percent of ruptures occurred at or close to full dilatation.
Failure to involve senior staff was common.
Delay in transfer to theatre (five cases).
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