Unit of delivery | 11338 | | <0.0001 | | | <0.0001 |
Hospital 1 | 3217 | 1 | | 1902 | 1 | |
Hospital 2 | 1763 | 1.56 (1.39 to 1.75) | | 1481 | 2.08 (1.75 to 2.46) | |
Hospital 3 | 840 | 0.81 (0.69 to 0.95) | | 644 | 0.78 (0.63 to 0.97) | |
Hospital 4 | 2467 | 0.99 (0.89 to 1.11) | | 2091 | 1.13 (0.96 to 1.31) | |
Hospital 5 | 3051 | 1.00 (0.91 to 1.11) | | | –§ | |
Mode of delivery | 9974 | | <0.0001 | | | <0.0001 |
Normal vaginal | 8565 | 1 | | 5152 | 1 | |
Assisted vaginal | 1409 | 0.21 (0.18 to 0.24) | | 966 | 0.50 (0.42 to 0.61) | |
Caesarean section | | –‡ | | | | |
Gestation (weeks) | 8157 | | <0.0001 | | | 0.001 |
35–37 | 595 | 0.62 (0.52 to 0.74) | | 348 | 0.65 (0.49 to 0.86) | |
38–40 | 5196 | 1 | | 3955 | 1 | |
>40 | 2366 | 0.89 (0.81 to 0.99) | | 1815 | 1.13 (0.98 to 1.29) | |
Parity | 7270 | | <0.0001 | | | <0.0001 |
Primiparous | 3452 | 0.11 (0.10 to 0.12) | | 2759 | 0.09 (0.08 to 0.10) | |
Multiparous | 3818 | 1 | | 3359 | 1 | |
Maternal age (years) | 11338 | | <0.0001 | | | 0.04 |
<20 | 1434 | 0.46 (0.40 to 0.52) | | 788 | 1.11 (0.89 to 1.38) | |
20–24 | 2554 | 0.91 (0.82 to 1.01) | | 1380 | 1.01 (0.85 to 1.21) | |
25–29 | 3477 | 1 | | 1849 | 1 | |
30–34 | 2652 | 1.02 (0.92 to 1.12) | | 1475 | 0.84 (0.71 to 1.00) | |
>35 | 1221 | 1.06 (0.93 to 1.21) | | 626 | 0.77 (0.62 to 0.96) | |
Birth weight | 8284 | | <0.0001 | | | <0.0001 |
<2500 g | 294 | 0.40 (0.31 to 0.53) | | 161 | 0.44 (0.29 to 0.66) | |
2500–4499 g | 7854 | 1 | | 5864 | 1 | |
>4499 g | 136 | 0.82 (0.58 to 1.16) | | 93 | 0.50 (0.32 to 0.79) | |
Feeding at hospital discharge | 8137 | | <0.0001 | | | 0.003 |
Formula | 4674 | 1 | | 3508 | 1 | |
Breast | 3368 | 0.73 (0.67 to 0.80) | | 2555 | 0.87 (0.76 to 1.00) | |
Mixed | 95 | 0.57 (0.37 to 0.88) | | 55 | 0.39 (0.21 to 0.74) | |
Deprivation quintile | 11203 | | <0.0001 | | | 0.008 |
1 | 2251 | 1 | | 1321 | 1 | |
2 | 2239 | 1.03 (0.91 to 1.16) | | 1206 | 1.07 (0.89 to 1.30) | |
3 | 2239 | 1.26 (1.12 to 1.42) | | 1178 | 1.27 (1.04 to 1.55) | |
4 | 2223 | 1.52 (1.35 to 1.71) | | 1170 | 1.35 (1.10 to 1.65) | |
5 | 2251 | 1.73 (1.54 to 1.95) | | 1243 | 1.37 (1.12 to 1.67) | |