Characteristics | All singleton births (N = 381,345) | Preterm births | |||
---|---|---|---|---|---|
No. | % | OR (95% CI) | AOR (a)(95% CI) | ||
Maternal age | |||||
Less than 25 | 76,182 | 6,012 | 7.9 | 1.27 (1.23–1.31) | 1.12 (1.08–1.16) |
25-34 | 223,494 | 14,130 | 6.3 | 1 | 1 |
35-44 | 81,216 | 5,673 | 7.0 | 1.11 (1.08–1.15) | 1.13 (1.09–1.17) |
45 and over | 439 | 44 | 10.0 | 1.65 (1.21–2.25) | 1.49 (1.08–2.06) |
Smoking status during pregnancy | |||||
Smoked | 47,179 | 4,569 | 9.7 | 1.64 (1.59–1.70) | 1.55 (1.50–1.61) |
Did not smoke | 196,661 | 12,050 | 6.1 | 1 | 1 |
Maternal country of birth | |||||
Overseas | 85,083 | 5,464 | 6.4 | 0.93 (0.90–0.96) | NS |
Australia | 294,196 | 20,211 | 6.9 | 1 | |
SEIFA Index of Disadvantage | |||||
1 (Most disadvantaged) | 78,473 | 5,919 | 7.5 | 1.28 (1.23–1.34) | 1.14 (1.09–1.19) |
2 | 62,969 | 4,565 | 7.3 | 1.23 (1.18–1.28) | 1.11 (1.06–1.17) |
3 | 83,153 | 5,543 | 6.7 | 1.12 (1.08–1.17) | 1.05 (1.00–1.10) |
4 | 87,116 | 5,516 | 6.3 | 1.06 (1.02–1.11) | 1.02 (0.98–1.07) |
5 (Least disadvantaged) | 66,987 | 4,007 | 6.0 | 1 | 1 |
Parity | |||||
Primiparous | 154,519 | 11,397 | 7.4 | 1.17 (1.14–1.20) | 1.13 (1.10–1.17) |
Multiparous | 226,826 | 14,474 | 6.4 | 1 | 1 |
Remoteness | |||||
Major cities | 244,632 | 15,951 | 6.5 | 1 | 1 |
Inner regional | 80,205 | 5,732 | 7.2 | 1.10 (1.07–1.14) | 1.00 (0.97–1.04) |
Outer regional | 44,867 | 3,216 | 7.2 | 1.11 (1.06–1.15) | 1.01 (0.96–1.05) |
Remote | 7,082 | 528 | 7.5 | 1.15 (1.06–1.26) | 1.04 (0.95–1.14) |
Very remote | 4,252 | 371 | 8.7 | 1.37 (1.23–1.53) | 1.13 (1.01–1.27) |
Health insurance | |||||
Public | 256,511 | 18,612 | 7.3 | 1 | 1 |
Private | 122,987 | 7,207 | 5.9 | 0.80 (0.77–0.82) | 0.89 (0.86–0.92) |
Essential hypertension | |||||
Yes | 3,468 | 511 | 14.7 | 2.41 (2.19–2.65) | 2.05 (1.86–2.27) |
No | 371,934 | 24,921 | 6.7 | 1 | 1 |
Diabetes mellitus | |||||
Yes | 2,447 | 606 | 24.8 | 4.62 (4.21–5.06) | 4.13 (3.75–4.56) |
No | 372,954 | 24,826 | 6.7 | 1 | 1 |
Epilepsy | |||||
Yes | 2,007 | 219 | 10.9 | 1.10 (1.00–1.21) | 1.49 (1.29–1.73) |
No | 373,395 | 25,213 | 6.8 | 1 | 1 |
Hypertensive disorders in pregnancy | |||||
Yes | 16,850 | 2,778 | 16.5 | 2.92 (2.80–3.05) | 2.94 (2.81–3.08) |
No | 364,495 | 23,093 | 6.3 | 1 | 1 |
Gestational diabetes | |||||
Yes | 19,075 | 1,639 | 8.6 | 1.31 (1.24–1.38) | 1.27 (1.20–1.34) |
No | 362,270 | 24,232 | 6.7 | 1 | 1 |
Antepartum haemorrhage | |||||
Yes | 10,699 | 3,311 | 31.0 | 6.92 (6.62–7.22) | 7.11 (6.80–7.43) |
No | 370,632 | 22,557 | 6.1 | 1 | 1 |