Adjusted incidence rate ratio for infant mortality in preterm babies, by area deprivation (IMD quintile relative to 1=advantaged), with 95% CI
| Cause of death | Congenital anomalies | Immaturity-related | Other causes | All causes |
| Gestation at birth | ||||
|---|---|---|---|---|
| 24–27 weeks | ||||
| 1=advantaged | 1.00 | 1.00 | 1.00 | 1.00 |
| 2 | 0.89 (0.44 to 1.83) | 0.92 (0.80 to 1.06) | 0.77 (0.51 to 1.17) | 0.90 (0.79 to 1.02) |
| 3 | 1.45 (0.78 to 2.71) | 1.01 (0.89 to 1.16) | 1.01 (0.69 to 1.46) | 1.03 (0.92 to 1.16) |
| 4 | 1.61 (0.89 to 2.91) | 1.09 (0.96 to 1.23) | 0.78 (0.55 to 1.13) | 1.07 (0.96 to 1.19) |
| 5=disadvantaged | 1.90 (1.08 to 3.34) | 1.04 (0.92 to 1.17) | 0.99 (0.71 to 1.39) | 1.07 (0.97 to 1.19) |
| Χ2 for variation | 11.3, p=0.02 | 8.0, p=0.09 | 5.3, p=0.3 | 13.5, p=0.009 |
| 28–31 weeks | ||||
| 1=advantaged | 1.00 | 1.00 | 1.00 | 1.00 |
| 2 | 0.97 (0.62 to 1.52) | 0.95 (0.72 to 1.25) | 2.59 (1.42 to 4.71) | 1.12 (0.90 to 1.39) |
| 3 | 1.08 (0.71 to 1.64) | 0.85 (0.65 to 1.11) | 2.13 (1.17 to 3.89) | 1.04 (0.84 to 1.28) |
| 4 | 1.20 (0.81 to 1.78) | 0.87 (0.67 to 1.12) | 2.36 (1.33 to 4.19) | 1.10 (0.91 to 1.34) |
| 5=disadvantaged | 1.38 (0.95 to 2.00) | 0.91 (0.72 to 1.16) | 2.26 (1.29 to 3.96) | 1.17 (0.97 to 1.41) |
| Χ2 for variation | 6.1, p=0.2 | 2.0, p=0.7 | 10.3, p=0.04 | 3.8, p=0.4 |
| 32–36 weeks | ||||
| 1=advantaged | 1.00 | 1.00 | 1.00 | 1.00 |
| 2 | 1.41 (1.09 to 1.83) | 1.18 (0.72 to 1.96) | 1.16 (0.83 to 1.62) | 1.30 (1.07 to 1.57) |
| 3 | 1.16 (0.90 to 1.50) | 0.98 (0.59 to 1.62) | 1.31 (0.95 to 1.80) | 1.19 (0.99 to 1.43) |
| 4 | 1.35 (1.07 to 1.72) | 1.18 (0.74 to 1.88) | 1.76 (1.31 to 2.35) | 1.46 (1.23 to 1.74) |
| 5=disadvantaged | 1.54 (1.22 to 1.93) | 1.17 (0.75 to 1.83) | 2.05 (1.55 to 2.72) | 1.65 (1.40 to 1.95) |
| Χ2 for variation | 18.8, p=0.0009 | 1.4, p=0.8 | 43.6, p<0.0001 | 50.5, p<0.0001 |
Live singleton births at 24–36 weeks , England and Wales 2006–2012. Stratified by gestational age at birth (completed weeks) and cause of death. Adjusted for ethnicity (nine groups), birth year and gestation week. All models have acceptable goodness-of-fit (Pearson p>0.1). P-value from Wald test for socioeconomic variation shown in bold if statistically significant, with Bonferroni significance level 0.0021 to compensate for multiple tests.
IMD, Index of Multiple Deprivation.