Table 1 Case-mix characteristics of the study population, NSW, 2007–2011. The study population consists of multiparous women with a singleton cephalic-presenting infant at ≥37 weeks gestation with at least one previous caesarean section
Variables and levels | Â | All deliveries | Any repeat caesareana | Planned repeat CS | Intrapartum repeat CS | Vaginal birth after caesarean | Planned vaginal birthb |
|---|---|---|---|---|---|---|---|
| Â | Â | N=61894 (column %) | N = 50819 (column %) | N=45006 (column %) | N=5813 (column %) | N = 11075 (column %) | N=16888 (column %) |
Maternal age | Under 20 | 314 (0.5) | 248 (0.5) | 211 (0.5) | 37 (0.6) | 66 (0.6) | 103 (0.6) |
| Â | 20 to 34 | 36626 (59.2) | 29472 (58.0) | 25843 (57.4) | 3629 (62.4) | 7154 (64.6) | 10783 (63.9) |
| Â | 35+ | 24954 (40.3) | 21099 (41.5) | 18952 (42.1) | 2147 (36.9) | 3855 (34.8) | 6002 (35.5) |
Country of birth | Australia or New Zealand | 45012 (72.9) | 37018 (73.0) | 32947 (73.4) | 4071 (70.2) | 7994 (72.3) | 12065 (71.6) |
| Â | Europe or North America | 3554 (5.8) | 2921 (5.8) | 2575 (5.7) | 346 (6.0) | 633 (5.7) | 979 (5.8) |
| Â | Other | 13177 (21.3) | 10750 (21.2) | 9368 (20.9) | 1382 (23.8) | 2427 (22.0) | 3809 (22.6) |
Model of care | Public patient in public hospital | 36059 (58.2) | 28020 (55.1) | 24079 (53.5) | 3941 (67.8) | 8039 (72.6) | 11980 (70.9) |
| Â | Private patient in public hospital | 5544 (9.0) | 4667 (9.2) | 4201 (9.3) | 466 (8.0) | 877 (7.9) | 1343 (8.0) |
| Â | Private patient in private hospital | 20291 (32.8) | 18132 (35.7) | 16726 (37.2) | 1406 (24.2) | 2159 (19.5) | 3565 (21.1) |
Smoking in pregnancy | 6174 (10.0) | 4599 (9.1) | 3947 (8.8) | 652 (11.2) | 1575 (14.2) | 2227 (13.2) | |
Diabetes (pre-existing or gestational) | 5233 (8.5) | 4598 (9.0) | 4166 (9.3) | 432 (7.4) | 635 (5.7) | 1067 (6.3) | |
Hypertensive disorders | 3327 (5.4) | 2842 (5.6) | 2510 (5.6) | 332 (5.7) | 485 (4.4) | 817 (4.8) | |
Other chronic medical conditionsc | 788 (1.3) | 709 (1.4) | 625 (1.4) | 84 (1.4) | 79 (0.7) | 163 (1.0) | |
Parity 2 or more (compared to parity 1) | 23911 (38.7) | 18516 (36.5) | 17132 (38.2) | 1384 (23.8) | 5395 (48.8) | 6779 (40.2) | |
2 or more previous caesarean sections | 13554 (22.0) | 13353 (26.4) | 12831 (28.6) | 522 (9.0) | 201 (1.9) | 723 (4.3) | |
Labour/vaginal birth prior to first caesarean | 5819 (9.4) | 3851 (7.6) | 3383 (7.5) | 468 (8.1) | 1968 (17.8) | 2436 (14.4) | |
Previous vaginal birth after caesarean | 4130 (6.7) | 1121 (2.2) | 834 (1.9) | 287 (4.9) | 3009 (27.2) | 3296 (19.5) | |
Previous 3rd or 4th degree perineal tear | 551 (0.9) | 402 (0.8) | 372 (0.8) | 30 (0.5) | 149 (1.3) | 179 (1.1) | |
Previous perinatal death | 1000 (1.6) | 825 (1.6) | 752 (1.7) | 73 (1.3) | 175 (1.6) | 248 (1.5) | |
Non-CS uterine scar | 421 (0.7) | 403 (0.8) | 377 (0.8) | 26 (0.4) | 18 (0.2) | 44 (0.3) | |
Assisted reproductive technology use, last 12 months | 1914 (3.1) | 1594 (3.1) | 1447 (3.2) | 147 (2.5) | 320 (2.9) | 467 (2.8) | |
Inter-pregnancy interval (months) | 0-17 | 21126 (34.1) | 17082 (33.6) | 15136 (33.6) | 1946 (33.5) | 4044 (36.5) | 5990 (35.5) |
| Â | 18-59 | 27761 (44.9) | 23069 (45.4) | 20617 (45.8) | 2452 (42.2) | 4692 (42.4) | 7144 (42.3) |
| Â | 60+ | 4903 (7.9) | 4066 (8.0) | 3605 (8.0) | 461 (7.9) | 837 (7.6) | 1298 (7.7) |
| Â | Unknown | 8104 (13.1) | 6602 (13.0) | 5648 (12.5) | 954 (16.4) | 1502 (13.6) | 2456 (14.5) |
Placental conditionsd | 1079 (1.7) | 990 (1.9) | 807 (1.8) | 183 (3.1) | 89 (0.8) | 272 (1.6) | |
Gestational age (weeks) | 37 | 4597 (7.4) | 3870 (7.6) | 3320 (7.4) | 550 (9.5) | 727 (6.6) | 1277 (7.6) |
| Â | 38 | 19452 (31.4) | 17579 (34.6) | 16389 (36.4) | 1190 (20.5) | 1873 (16.9) | 3063 (18.1) |
| Â | 39 | 25143 (40.6) | 21915 (43.1) | 20366 (45.3) | 1549 (26.6) | 3228 (29.1) | 4777 (28.3) |
| Â | 40 | 9016 (14.6) | 5367 (10.6) | 3782 (8.4) | 1585 (27.3) | 3649 (32.9) | 5234 (31.0) |
| Â | 41+ | 3686 (6.0) | 2088 (4.1) | 1149 (2.6) | 939 (16.2) | 1598 (14.4) | 2537 (15.0) |
Birth weight for gestational age | Small (<10th percentile) | 5,501 (8.9) | 4110 (8.1) | 3501 (7.8) | 609 (10.5) | 1391 (12.6) | 2000 (11.8) |
| Â | Appropriate | 49453 (79.9) | 40540 (79.8) | 35962 (79.9) | 4578 (78.8) | 8913 (80.5) | 13491 (79.9) |
| Â | Large (>90th percentile) | 6927 (11.2) | 6158 (12.1) | 5533 (12.3) | 625 (10.8) | 769 (6.9) | 1394 (8.3) |
Stillbirth | 60 (0.1) | 30 (0.1) | 23 (0.1) | 7 (0.1) | 30 (0.3) | 37 (0.2) | |
Severe maternal morbidity | 654 (1.9) | 526 (1.9) | 395 (1.6) | 131 (4.0) | 128 (2.1) | 259 (2.8) | |
Severe neonatal morbidity | 1275 (2.1) | 1058 (2.1) | 851 (1.9) | 207 (3.6) | 217 (2.0) | 424 (2.5) | |
Postpartum haemorrhage | 2847 (4.6) | 1666 (3.3) | 1301 (2.9) | 365 (6.3) | 1181 (10.7) | 1546 (9.2) | |
Apgar score at five minutes <7 | 520 (0.8) | 371 (0.7) | 261 (0.6) | 110 (1.9) | 149 (1.4) | 259 (1.5) | |