Uterine rupture after previous caesarean section

To determine the risk factors, percentage and maternal and perinatal complications of uterine rupture after previous caesarean section.

Population-based registry study.

Mothers with births > or =28 weeks of gestation after previous caesarean section (n = 18 794), registered in the Medical Birth Registry of Norway, from 1 January 1999 to 30 June 2005.

Associations of uterine rupture with risk factors, maternal and perinatal outcome were estimated using cross-tabulations and logistic regression.

Odds of uterine rupture.

A total of 94 uterine ruptures were identified (5.0/1000 mothers). Compared with elective prelabour caesarean section, odds of rupture increased for emergency prelabour caesarean section (OR: 8.63; 95% CI: 2.6-28.0), spontaneous labour (OR: 6.65; 95% CI: 2.4-18.6) and induced labour (OR: 12.60; 95% CI: 4.4-36.4). The odds were increased for maternal age > or =40 years versus <30 years (OR: 2.48; 95% CI: 1.1-5.5), non-Western (mothers born outside Europe, North America or Australia) origin (OR: 2.87; 95% CI: 1.8-4.7) and gestational age > or =41 weeks versus 37-40 weeks (OR: 1.73; 95% CI: 1.1-2.7). Uterine rupture after trial of labour significantly increased severe postpartum haemorrhage (OR: 8.51; 95% CI: 4.6-15.1), general anaesthesia exposure (OR: 14.20; 95% CI: 9.1-22.2), hysterectomy (OR: 51.36; 95% CI: 13.6-193.4) and serious perinatal outcome (OR: 24.51 (95% CI: 11.9-51.9). Induction by prostaglandins significantly increased the odds for uterine rupture compared with spontaneous labour (OR: 2.72; 95% CI: 1.6-4.7). Prelabour ruptures occurred after latent uterine activity or abdominal pain in mothers with multiple or uncommon uterine scars.

Trial of labour carried greater risk and graver outcome of uterine rupture than elective repeated caesarean section, although absolute risks were low. A review of labour management and induction protocol is needed.