Growth and mineral metabolism in very low birth weight infants. II. Effects of calcium supplementation on growth and divalent cations.

Infants of two groups, one of 16, one of 14 infants, who weighed less than 1.3 kg at birth (mean 1.01 +/- 0.05 kg), were studied from age 14 days until they reached 1.8 kg body weight. Infants were pair-matched for gestational age and birth weight and one member was randomly allocated to two treatment groups. Infants in group A received no calcium supplement and those in group B received calcium lactate, 800 mg/kg/24 hr hr, in divided doses with each feed. All were fed "Improved" SMA, 200 ml/kg/24 hr, 160 cal/kg/24 hr, and were given a multivitamin preparation containing 500 IU vitamin D2/dose. The infants' weekly length gain did not differ between groups (1.08 +/- 0.04 cm/week vs 1.11 +/- 0.04 cm/week; mean +/- SEM). Mean weight and head cercumference increments also were similar (group A, 163 +/- 6 g/week; 1.12 +/- 0.03 cm/week; group B, 170 +/- 6 g/week and 1.18 +/- 0.03 cm/week). An increase in blood pH from 7.33 +/- 0.01 to 7.41 +/- 0.01 (P less than 0.01) in group A babies was associated with a decrease in PCO2 from 44.2 +/- 1.0 to 38.9 +/- 1.4 mm Hg. Values remained unchanged with age in group B babies...