Emergency CS: distribution of deliveries (all singleton deliveries without deliveries by elective CS) and proportion of emergency CS according to risk factors
| Singleton deliveries minus elective CS | Deliveries | Emergency CS | ||
| n (%) | n (% within category) | OR | 95% CI | |
| 206 992 (100) | 26 305 (12.7) | |||
| Year | ||||
| 2009 | 53 614 (27) | 7003 (13.1) | Ref | |
| 2010 | 54 166 (27) | 7023 (13.0) | 0.96 | 0.92 to 1.00 |
| 2011 | 50 326 (24) | 6271 (12.5) | 0.90 | 0.86 to 0.94 |
| 2012 | 48 886 (24) | 6008 (12.3) | 0.93 | 0.89 to 0.98 |
| Size of maternity unit | ||||
| Small | 12 754 (6) | 1464 (11.5) | 1.02 | 0.95 to 1.09 |
| Medium | 88 907 (43) | 11 292 (12.7) | Ref | |
| Large | 105 331 (51) | 13 549 (12.9) | 0.90 | 0.87 to 0.93 |
| Weekend delivery (yes) | 60 733 (29) | 7763 (12.8) | 1.00 | 0.97 to 1.03 |
| Night delivery (yes) | 100 357 (48) | 12 046 (12.0) | 0.93 | 0.90 to 0.95 |
| Maternal age (years) | ||||
| 15–19 | 3199 (2) | 309 (9.7) | 0.60 | 0.52 to 0.69 |
| 20–34 | 163 543 (79) | 20 034 (12.3) | Ref | |
| 35–44 | 40 250 (19) | 5962 (14.8) | 1.48 | 1.42 to 1.53 |
| Maternal smoking (yes) | 25 993 (13) | 3571 (13.7) | 1.10 | 1.05 to 1.15 |
| Maternal BMI | ||||
| 14.0–18.4 | 8679 (4) | 774 (8.9) | 0.77 | 0.70 to 0.84 |
| 18.5–24.9 | 131 611 (64) | 14 658 (11.1) | Ref | |
| 25.0–29.9 | 42 138 (20) | 6147 (14.6) | 1.34 | 1.29 to 1.39 |
| 30–34.9 | 16 198 (8) | 2929 (18.1) | 1.75 | 1.66 to 1.84 |
| 35.0+ | 8366 (4) | 1797 (21.5) | 2.07 | 1.94 to 2.22 |
| Maternal height≤163 cm (yes) | 49 899 (24) | 8701 (17.4) | 1.67 | 1.62 to 1.73 |
| Parity | ||||
| Nulliparous | 99 149 (48) | 16 712 (16.9) | Ref | |
| Multiparous without previous CS | 92 311 (45) | 3985 (4.3) | 0.25 | 0.24 to 0.27 |
| Multiparous with previous CS | 15 532 (8) | 5608 (36.1) | 2.97 | 2.84 to 3.10 |
| Complication factors | ||||
| Diabetes | 380 (0.2) | 74 (19.5) | ||
| Hypertension | 3598 (2) | 707 (19.6) | ||
| Pre-eclampsia/eclampsia | 5872 (3) | 2110 (35.9) | ||
| Placenta praevia | 617 (0.3) | 420 (68.1) | ||
| Placental abruption | 967 (0.5) | 622 (64.3) | ||
| Premature rupture of membranes | 17 450 (8) | 3536 (20.3) | ||
| Complication (yes) | 28 087 (14) | 7129 (25.4) | 1.98 | 1.90 to 2.06 |
| Augmentation of labour (yes) | 59 228 (29) | 9825 (16.6) | 1.01 | 0.98 to 1.05 |
| Any induced labour (yes) | 38 767 (19) | 7128 (18.4) | 1.40 | 1.35 to 1.46 |
| Induced by medication | 27 166 (13) | 5303 (19.5) | ||
| Induced by operation | 21 359 (10) | 3882 (18.2) | ||
| Term | ||||
| <37+0 | 10 377 (5) | 3823 (36.8) | 2.94 | 2.77 to 3.12 |
| 37+0–41+6 | 186 441 (90) | 20 400 (10.9) | Ref | |
| ≥42+0 | 10 174 (5) | 2082 (20.5) | 1.77 | 1.67 to 1.89 |
| Female baby (yes) | 100 585 (49) | 11 923 (11.9) | 0.88 | 0.85 to 0.91 |
| Breech (yes) | 4597 (2) | 3607 (78.5) | 43.73 | 40.01 to 47.79 |
| Fetal distress (yes) | 42 963 (21) | 9803 (22.8) | 2.37 | 2.28 to 2.45 |
| Cephalopelvic disproportion (yes) | 3911 (2) | 2551 (65.2) | 13.96 | 12.91 to 15.1 |
| Macrosomia (yes) | 5642 (3) | 1173 (20.8) | 2.58 | 2.38 to 2.79 |
OR with 95% CI based on a multivariable logistic regression model.
BMI, body mass index; CS, caesarean section; n, Number; Ref, reference group.