['Serum concentrations of conventional nutrition-related proteins, such as albumin, prealbumin, transferrin, and retinol-binding protein, are usually inconsistent with changes in anthropometric measurements in the postnatal period. The aim of this study was to evaluate how reliable growth hormone (GH), insulin-like growth factors (IGFs), IGF-binding proteins (IGFBPs), and leptin, the proteins known to be involved in the regulation of growth, are in reflecting postnatal growth and nutritional status in preterm neonates.', 'Blood samples and anthropometric measurements were collected from 55 preterm neonates (chronological age 30.4 +/- 2.8 weeks) for 4 continuous weeks (weeks 0 to 3).', 'After adjusting for chronological age, body weights and serum IGF-II concentrations were significantly greater and serum transferrin concentrations were significantly lower in weeks 2 and 3 than in week 0 (repeated-measures analysis of variance (ANOVA) and Bonferroni test, p < .05). Forward stepwise multivariate regression analysis showed that change in total IGF-I (week 0 to week 3) was a positive predictor, and changes in insulin and prealbumin were negative predictors of postnatal weight gain. In addition, daily fat intake was a positive predictor of postnatal length increases, and changes in prealbumin, insulin, and GH were negative predictors of postnatal changes in the ponderal index (weight x length(-3)). Changes in GH and IGFBP-2 were negative predictors of changes in head circumference and triceps skinfold thickness, respectively.'] Are changes in serum insulin-like growth factors , not leptin , associated with postnatal weight gain in preterm neonates?