Gestational age category | |||||
---|---|---|---|---|---|
Year | NZDep Index Decile | All preterm (n=51 711) OR* | 20–27 weeks (n=2697) OR** | 28–33 weeks (n=12 703) OR* | 34–36 weeks (n=36 311) OR* |
Multivariate analysis adjusted for gender, maternal age, parity, birth year, decile and birth year*decile, year*age, year*parity, decile*age, decile*parity. | |||||
*Odds ratios (OR) with reference category Deprivation Index decile 1, 1980. | |||||
**Odds ratios for the 20–27 week category did not reach statistical significance. | |||||
1980 | 1 | 1.00 | 1.00 | 1.00 | 1.00 |
1980 | 5 | 1.15 | 1.08 | 1.16 | 1.15 |
1980 | 10 | 1.36 | 1.18 | 1.39 | 1.36 |
1990 | 1 | 1.30 | 1.31 | 1.21 | 1.33 |
1990 | 5 | 1.44 | 1.45 | 1.34 | 1.47 |
1990 | 10 | 1.63 | 1.66 | 1.52 | 1.67 |
1999 | 1 | 1.64 | 1.67 | 1.44 | 1.72 |
1999 | 5 | 1.76 | 1.91 | 1.53 | 1.84 |
1999 | 10 | 1.93 | 2.25 | 1.64 | 2.02 |