From: Rate of spontaneous onset of labour before planned repeat caesarean section at term
 | Total low risk women N = 17,314 | Spontaneous labour <39 weeks N = 1,473 | Crude RR (95% CI) | Adjusted RRb(95% CI) | |
---|---|---|---|---|---|
 |  | N | Rate (Row%)a |  |  |
Age (years) | Â | Â | Â | Â | Â |
<20 | 106 | 10 | 9.4 | 1.12 (0.62, 2.02) | Â |
20 - <35 | 10,927 | 922 | 8.4 | 1.00 | Â |
> = 35 | 6,280 | 541 | 8.6 | 1.02 (0.92, 1.13) |  |
Country of birth | |||||
Australian | 12,663 | 1,013 | 8.0 | 1.00 | 1.00 |
Asian | 2,238 | 258 | 11.5 | 1.44 (1.27, 1.64) | 1.53 (1.33, 1.75) |
Other | 2,376 | 199 | 8.4 | 1.05 (0.91, 1.21) | 1.09 (0.94, 1.26) |
Socio-economic status | |||||
Most disadvantaged | 3,144 | 293 | 9.3 | 1.00 | Â |
Disadvantaged | 3,017 | 254 | 8.4 | 0.90 (0.77, 1.06) | Â |
Average | 2,997 | 263 | 8.8 | 0.94 (0.80, 1.10) | Â |
Advantaged | 3,341 | 259 | 7.8 | 0.83 (0.71, 0.98) | Â |
Most advantaged | 4,596 | 386 | 8.4 | 0.90 (0.78, 1.04) | Â |
Smoking in pregnancy | 1,561 | 176 | 11.3 | 1.37 (1.18, 1.59) | 1.33 (1.14, 1.56) |
No. of previous vaginal births | |||||
0 | 14,972 | 1,256 | 8.4 | 1.00 | 1.00 |
1 | 1,394 | 133 | 9.5 | 1.14 (0.96, 1.35) | 0.94 (0.80-1.12) |
≥2 | 531 | 53 | 10.0 | 1.19 (0.92, 1.54) | 0.89 (0.68-1.15) |
No. of previous CS | |||||
1 | 12,562 | 1,013 | 8.1 | 1.00 | 1.00 |
2 | 3,673 | 358 | 9.8 | 1.21 (1.07, 1.35) | 1.16 (1.04, 1.30) |
≥3 | 703 | 73 | 10.4 | 1.28 (1.03, 1.61) | 1.16 (0.92, 1.45) |
Prior delivery history c | |||||
Spontaneous preterm | 402 | 102 | 25.4 | 4.31 (3.57, 5.20) | 4.12 (3.38, 5.03) |
Planned preterm | 447 | 65 | 14.5 | 2.49 (1.96, 3.16) | 2.47 (1.94, 3.14) |
Spontaneous term | 5,255 | 570 | 10.8 | 1.85 (1.65, 2.08) | 1.85 (1.65, 2.07) |
Planned term | 8,722 | 512 | 5.9 | 1.00 | 1.00 |
Unavailable | 2,488 | 224 | 9.0 | 1.54 (1.32, 1.79) | 1.39 (1.19, 1.63) |
Vertex Presentation | 16,911 | 1,440 | 8.5 | 1.04 (0.75, 1.45) | Â |
Size at birth | |||||
<10th percentile | 903 | 81 | 9.0 | 1.03 (0.83, 1.27) | Â |
10th - 90th percentile | 13,674 | 1,194 | 8.7 | 1.00 | Â |
>90th percentile | 2,729 | 197 | 7.2 | 0.83 (0.72, 0.96) | Â |
Care type (private) | 8,324 | 700 | 8.4 | 0.98 (0.89, 1.08) | Â |
Antenatal care (<20w) | 16,353 | 1,390 | 8.5 | 0.98 (0.80, 1.22) | Â |
Birth hospital type | |||||
Private | 6,597 | 533 | 8.1 | 0.96 (0.85, 1.08) | Â |
Tertiary | 5,743 | 483 | 8.4 | 1.00 | Â |
Other (urban) | 2,409 | 225 | 9.3 | 1.11 (0.96, 1.29) | Â |
Other (rural) | 2,565 | 232 | 9.0 | 1.08 (0.93, 1.25) | Â |