Calcium and phosphorus supplementation after initial hospital discharge in breast-fed infants of less than 1800 grams birth weight.

This study evaluated whether calcium and phosphorus supplementation after initial hospital discharge was advisable in infants of < 1800 gm birth weight who were being breast fed. Twenty-seven infants (15 without any illness affecting nutritional intake and 12 with medical illness) received breast milk plus a liquid human milk fortifier mixed 1:1 and 400 IU vitamin D daily during initial hospitalization. At discharge, 12 infants (6 without and 6 with previous illness) were randomly assigned to receive calcium and phosphorus supplementation, and 15 infants (9 without illness and 6 with previous illness) received no mineral supplementation. A third group of seven healthy infants received a formula for premature infants during initial hospitalization and a standard cow's milk formula (20 calories per ounce) after discharge. The mean plasma calcium, phosphorus, and alkaline phosphatase levels did not differ among the three groups at study entry. Eight weeks after discharge, eight infants (four without illness and four with illness) had hypophosphatemia < 4.5 mg/dl. All were breast fed, and seven of eight had not received posthospitalization calcium and phosphorus supplementation. The incidence of hypophosphatemia in infants with or without illness was significantly greater in infants who did not receive supplementation (p = 0.038). These data indicate that calcium, phosphorus, and vitamin D supplementation may be necessary in approximately 50% of breast-fed infants of < 1800 gm birth weight after hospital discharge. It is recommended that serum calcium, phosphorus, and alkaline phosphatase be measured 4 to 8 weeks after discharge to identify those infants who require supplementation.