“…In preterm infants, overhydration during the first week of life may induce patent ductus arteriosus (PDA), which is associated with the development of intraventricular hemorrhage, necrotizing enterocolitis, and bronchopulmonary dysplasia [ 3 , 4 ]. As newborns show a physiologically low glomerular filtration rate (GFR) and low urinary flow rate on the first day of life, they may be unable to increase water excretion and so can easily develop edema [ 5 , 6 ]. Therefore, tight control of volume is mandatory as well as glucose, electrolyte, acid-base status, urine output, oxygenation/ventilation, and temperature to premature infants with large fluid shift.…”