The mean birth weight was 1338.7 g for group 1, 1104.0 g for group 2 and 1254.7 g for group 3. Mean gestational age at birth was 31.9, 30.0 and 31.2 weeks, respectively, and mean corrected age at discharge was 37.8, 41.7 and 38.2 weeks, respectively. The groups were comparable, with no significant difference between them.