Characteristics of study population*. Values are percentages (numbers)
| Characteristic | Weekdays (n=1 012 119) | Weekends (n=320 716) | P value |
|---|---|---|---|
| Delivery method: | <0.001 | ||
| Spontaneous vertex | 59.7 (603 770) | 68.6 (219 858) | |
| Spontaneous, other cephalic | 0.5 (4700) | 0.5 (1719) | |
| Low forceps, non-breech | 3.9 (39 856) | 4.6 (14 771) | |
| Other forceps, non-breech | 2.1 (21 320) | 2.5 (7858) | |
| Ventouse, vacuum extraction | 6.1 (61 351) | 6.9 (22 097) | |
| Breech | 0.4 (4268) | 0.4 (1417) | |
| Breech extraction, not otherwise specified | 0.1 (546) | 0.1 (158) | |
| Elective caesarean | 12.7 (128 059) | 1.5 (4845) | |
| Emergency caesarean | 14.6 (147 627) | 14.9 (47 788) | |
| Other | 0.1 (622) | 0.1 (205) | |
| Maternal age (years): | <0.001 | ||
| <19 | 5.1 (51 850) | 5.8 (18 609) | |
| 20-24 | 18.4 (186 359) | 19.9 (63 889) | |
| 25-29 | 27.5 (278 540) | 28.2 (90 557) | |
| 30-34 | 28.6 (289 937) | 28.2 (90 374) | |
| 35-39 | 16.2 (164 047) | 14.6 (46 728) | |
| ≥40 | 4.1 (41 386) | 3.3 (10 559) | |
| Ethnicity: | <0.001 | ||
| White | 72.3 (731 968) | 71.8 (230 123) | |
| Asian | 10.3 (104 552) | 10.5 (33 565) | |
| Black (including black British, Afro-Caribbean) | 5.1 (51 678) | 5.0 (15 960) | |
| Mixed | 1.5 (15 033) | 1.5 (4827) | |
| Other (including Chinese) | 3.3 (33 073) | 3.4 (10 742) | |
| Unknown/not stated | 7.5 (75 815) | 8.0 (25 499) | |
| Carstairs deprivation fifth: | |||
| 1 (least deprived) | 15.2 (154 180) | 14.9 (47 870) | <0.001 |
| 2 | 16.3 (164 915) | 16.0 (51 404) | |
| 3 | 19.0 (192 353) | 18.9 (60 735) | |
| 4 | 22.0 (223 148) | 22.3 (71 498) | |
| 5 (most deprived) | 26.5 (268 635) | 27.0 (86 611) | |
| Unknown | 0.9 (8888) | 0.8 (2598) | |
| Primiparous | 43.5 (439 994) | 46.4 (148 751) | <0.001 |
| Gestational age (weeks): | <0.001 | ||
| <37 | 7.6 (76 578) | 7.4 (23 628) | |
| 37-39 | 35.7 (361 190) | 30.3 (97 062) | |
| 40-41 | 39.7 (402 103) | 45.1 (144 803) | |
| ≥42 | 3.6 (36 144) | 4.1 (13 061) | |
| Unknown | 13.5 (136 104) | 13.2 (42 162) | |
| Birth weight (g) | <0.001 | ||
| <2500 | 5.9 (60 114) | 5.4 (17 240) | |
| 2500-4000 | 74.1 (749 757) | 74.7 (239 644) | |
| ≥4000 | 10.0 (101 694) | 10.2 (32 580) | |
| Unknown | 9.9 (100 554) | 9.7 (31 252) | |
| Multifetal gestation: | <0.001 | ||
| Yes | 1.6 (16 263) | 0.9 (2887) | |
| No | 91.0 (921 329) | 91.8 (294 400) | |
| Unknown | 7.4 (74 527) | 7.3 (23 429) | |
| Previous caesarean section† | 12.8 (129 427) | 6.8 (21 955) | <0.001 |
| Induction of labour rates | 32.1 (324 627) | 32.6 (104 416) | <0.001 |
*Data are for maternities and are categorised by day of admission.
†Calculated using data extracted on caesarean sections since April 1996.