Table 1 Univariate obstetric associations with uterine rupture and perinatal death due to uterine rupture. Figures are numbers (percentages) unless stated otherwise

Uterine rupture Perinatal death due to uterine rupture Characteristics Yes (n=124) No (n=35 730) Relative risk (95% CI) P value* Yes (n=17) No (n=35 837) Relative risk (95% CI) P value* <3000 births a year 63 (50.8) 16 930 (47.4) 1.1 (0.8 to 1.6) 0.47 13 (76.5) 16 980 (47.4) 3.6 (1.2 to 11.1) 0.03 No previous vaginal birth 102 (82.3) 23 089 (64.6) 2.5 (1.6 to 4.0) <0.0001 15 (88.2) 23 176 (64.7) 4.1 (0.9 to 17.9) 0.04 Induction of labour without prostaglandin 13 (10.5) 4416 (12.4) 1.1 (0.6 to 2.0) 0.75 2 (11.8) 4427 (12.4) 1.2 (0.3 to 5.6) 0.68 Induction of labour with prostaglandin 39 (31.4) 4436 (12.4) 3.3 (2.2 to 4.8) <0.0001 5 (29.4) 4470 (12.5) 3.0 (1.0 to 8.8) 0.05 Gestation >41 weeks 8 (6.4) 1 867 (5.2) 1.2 (0.6 to 2.6) 0.54 0 (0.0) 1875 (5.2) — >0.9

^* Fisher's exact test (two sided).

Includes 35 730 women who did not have uterine rupture documented and 107 women who had uterine rupture documented but it did not result in stillbirth or neonatal death.

Same reference category for both: all women in whom labour was not induced.