Summary statistics for all Northern and Trent preterm babies born in 2000–3/4 without a lethal malformation
| Variable | Northern 2000–3 22–31 weeks (n = 1456) | Trent 2000–4 23–31 weeks (n = 3382) |
| Male sex | 54% (780) | 55% (1858) |
| Gestation, days | 204 (188–215) | _ |
| Gestation, completed weeks | 29 (26–30) | 29 (27–30) |
| Birth weight, z score | −0.3 (0.8) | −0.4 (0.8) |
| Birth weight, prenatal estimate, z score | −0.3 (1.1) | −0.4 (1.1) |
| Base deficit, mmol/l (n = 1154) | 5.0 (2.6, 7.8) | – |
| Stillborn | 1.5% (22) | 2.0% (68) |
| Died before term | 16% (235) | 17% (561) |
Results are % (n) or median (interquartile range) or mean (SD).