Maternal and fetal serum insulin-like growth factor-I (IGF-I), IGF bindingprotein-3 (IGFBP-3), leptin levels and early postnatal growth in infants born asymmetrically small for gestational age

This study was planned to investigate the relationship between birth weight and insulinlike growth factor-I (IGF-I), IGF binding protein-3 (IGFBP-3), and leptin levels in neonates with normal growth (appropriate for gestation al age: AGA) and retarded growth (small for gestational age: SGA); and to e valuate these growth factors' effects in early postnatal growth. All newbor ns were full-term: gestational age 38-41 weeks. Of 50 neonates, 25 were SGA . IGF-I, IGFBP-3 and leptin levels were measured in maternal serum and veno us cord blood at birth and at 15 days of life of neonates using specific RI As. Maternal serum leptin concentrations were significantly higher than cor d blood leptin concentrations (p<0.001). Maternal serum IGF-I, IGFBP-3 and leptin levels did not show correlations with birth weight. In contrast, the re were significantly positive correlations between birth weight and venous cord blood IGF-I, IGFBP-3 and leptin levels (p<0.001). In the SGA group, t he newborns with a slow postnatal growth pattern had lower umbilical cord s erum IGF-I levels compared with newborns with a normal growth pattern. A si milar result was also found in the AGA group. Similar results were not foun d for serum leptin and IGFBP-3. In conclusion, cord blood IGF-I, IGFBP-3 and leptin levels play an importan t role in the regulation of fetal and neonatal growth. It is likely that IG F-I has a more important role than the other factors in early postnatal gro wth.