 Design: VLBW preterm infants 32 weeks of gestational age were included in the study and randomized into two groups according to the method of breast milk fortification. In the targeted protein fortification group, breast milk samples were analyzed daily via mid-infrared spectroscopy and additional protein was provided to maintain an intake of 4.5 gkgday. In the adjustable protein fortification group, blood urea nitrogen BUN levels were monitored weekly, and if the level was 5 mgdL, the amount of protein fortification was gradually increased to an estimated maximum level of 4.5 gkgday, as per the policy of neonatal intensive care unit. The cumulative amounts of protein, energy, fat, and carbohydrate given to infants prior to study commencement and during the study period were calculated. Anthropometric measurements were performed in both groups weekly for 4 weeks to compare their growth, and blood data including pH, base deficit, and urea, creatinine, and albumin levels were collected. 