 Measurements of body weight, length, foot size, triceps skinfold, mid-arm circumference, and total body water will be taken at 5 moments in the premature infants: in the first 24 hours of life, at the 7th day of life after recovering birth weight, at term GA 37 42 weeks, and with weight from 2,800 to 3,200g. The two latter measurements may be taken after hospital discharge, during outpatient follow-up. These variables will be evaluated in the first 24 hours of life in the term newborns with weight from 2,800g to 3,200g. 