| Bronchopulmonary dysplasia | ||||
| None(n = 18) | Mild(n = 35) | Moderate and severe(n = 21) | p Value | |
| No (%) girls | 12 (63%) | 20 (53%) | 9 (38%) | 0.123* |
| Mean (SD) gestational age (weeks) | 28.1 (1.2) | 26.7 (1.4) | 26.3 (1.5) | <0.001† |
| Mean (SD) birth weight (g) | 1121.4 (160.6) | 968.0 (201.3) | 852.4 (169.7) | <0.001† |
| Median (range) days of ventilator treatment | 0.9 (0–4.8) | 8.9 (0–40.0) | 20.5 (1.7–54.5) | <0.001† |
| Median (range) days of oxygen therapy | 10 (1–26) | 45 (28–71) | 103 (55–257) | <0.001† |
p Values assess trends within the preterm population over increasing severity of neonatal bronchopulmonary dysplasia.
*χ2 test for trend. †Linear regression.