Estimated Fluid Requirements in Newborns

Used to guide daily maintenance fluids in term and preterm newborns—primarily during the first days of life when insensible losses, renal immaturity, and transition physiology make fluid needs variable. Clinically useful for preventing both dehydration and fluid overload, especially in extremely preterm infants where excess fluid increases risks of BPD and mechanical ventilation 1.

Start with 80–100 mL/kg/day in term newborns and adjust to gestational age, urine output, weight change, and electrolytes. Isotonic solutions reduce hyponatremia risk in term infants 1 [Level II evidence]. Avoid fluid overload due to higher mortality and morbidity in critically ill neonates 2 [Level II evidence]. Increase cautiously in extremely preterm infants because of higher transepidermal water loss.