Posthospitalization Growth and Bone Mineral Status of Normal Preterm Infants

Abstract

• The growth and bone mineralization were studied in ten preterm infants fed human milk and 14 preterm infants fed cow's milk–based formula. After discharge from the hospital, at 42, 48, and 56 weeks' postmenstrual age, anthropometric measures of weight, length, occipital frontal circumference, mid–upper arm circumference, triceps, and subscapular skin folds were obtained. Blood was drawn for determinations of serum calcium, phosphorus, 25-hydroxyvitamin D, alkaline phosphatase, and albumin levels. Bone mineral analyses were performed by photon absorptiometry. Mean (± SD) gestational ages in nursing and formula-fed Infants were similar (32.0±2.5 vs 31.5±1.5 weeks), as were their mean (±SD) birth weights (1.76±0.42 vs 1.52±0.30 kg). After hospitalization, both groups had similar rates of growth in weight, length, head circumference, mid–upper arm circumference, triceps, and subscapular skin-fold thickness. The formula-fed group had higher serum phosphorus levels at 42 weeks, higher serum calcium levels at 48 weeks, and higher serum albumin concentrations at 56 weeks than the breast-fed group. By 56 weeks' postmenstrual age, the bone mineral content was higher In the formula-fed group. Our data suggest that after hospitalization, preterm Infants fed their own mother's milk have similar growth patterns but a different bone mineralization rate compared with preterm infants fed a standard cow's milk–based formula. (AJDC 1985;139:896-898)