Study design This is an interventional, randomized, controlled study.~Description of the study The very premature newborn will be identified by daily evaluation of the infants admitted for consultation in the income book.~Informed consent will be requested from the infant´s father, mother or legal guardian between the fifth and tenth day of life.~Fortification will be done according to the randomization group.~Outline of the study design~Excel calculation sheet of individualized supplementation according to the composition of breast milk in the target fortification group. Methodology of analysis of breast milk in FOSS analyzer.~In the adjusted fortification group, urea concentration levels will be kept between 19-30 mg / dL~Fenton curves or https://www.growthcalculator.org/ will be used for Z-scores calculation.~Growth speed calculation: Weight gain: (1000x ln [Final weight / Initial weight]) / number of days.~4 Duration of the study for each participant The duration of participation in the study and the fortification intervention period will be a maximum of 132 days.
Investigation about the effect on weight gain in extremely low birth weight preterm with individualized fortification, according to human milk analysis versus fortification adjusted according to urea serum concentration.