The primary aim of this study is to investigate the relationship between early plasma protein levels and hemodynamics in very preterm infants during postnatal transition. Secondary aims are the following: i) to evaluate maternal and neonatal factors affecting plasma protein level at birth; ii) to evaluate the relationship between plasma protein level and albumin level on the first day of life; iii) to evaluate the association between early hypoproteinemia and neonatal mortality and morbidity in very preterm infants.