Early follow-up of very low birth weight infants after hospital discharge with respect to growth and mineral homeostasis.

Very low birth weight infants from two previous in-hospital feeding studies were investigated at follow-up after hospital discharge at a mean postnatal age of 12 weeks. Of infants who had received human milk in hospital (own mother's or pooled), 26 were seen at follow-up, of whom only 8 remained exclusively breast fed. Of those fed a formula in hospital, 31 were seen at follow-up. Those infants who had been fed human milk while in hospital demonstrated slower linear growth over the 6-week period of this study. Only those fed exclusively human milk from birth to the time of follow-up showed elevated serum alkaline phosphatase and low serum phosphate values, while those fed human milk in hospital, but completely or partially formula fed thereafter, had values similar to those fed formula throughout. Alkaline phosphatase values greater than 675 IU/L were associated with either exclusive breast feeding or vitamin D depletion. Of the two cases of rickets diagnosed on wrist x-rays, one infant had been exclusively breast fed and the other was vitamin D depleted.