IRCT20141118019991N3 IRCT 2021-09-16 Tehran University of Medical Sciences Effect of increasing the amount of milk protein content by protein supplement on growth indices of preterm infants Evaluating the effect of increasing the amount of milk protein content by protein supplement on growth indices of preterm infants 2014-03-20 anticipated 30 Complete https://irct.ir/trial/17742 interventional Randomization: Randomized, Blinding: Double blinded, Placebo: Not used, Assignment: Parallel, Purpose: Supportive, Randomization description: We will Use permuted block randomization and assign participants 1:1 to the standard of care diet (control) or higher protein Diet (intervention). Twins will be randomized individually. The study biostatistician will generate the allocation sequence and place the research assignments in envelopes, to be opened by research assistants on the study start date, Blinding description: Parents, clinical staff, and all study staff apart from the research assistants who prepare the study diet will be blinded to the study group. Unblinding will be permitted if an error in milk preparation is identified, or if unexpected safety concerns arise that require unblinding. N/A Very Low Birth Weight. Intervention 1: Intervention group: High protein diet (4 grams per kilogram per day)  which is provided by protein supplement, when the enteral feeding has been started. Intervention 2: Control group: Routine protein diet (3.5 grams per kilogram per day)  which is provided by protein supplement, when the enteral feeding has been started. No - There is not a plan to make this available Justification or reason for not sharing IPD is No more information.