Growth of very premature infants fed intravenous hyperalimentation and calcium-supplemented formula.

OBJECTIVE: To describe growth during initial hospitalization for very small premature infants fed intravenous hyperalimentation, then calcium supplemented 1460 mg/L (36.5 mmol/L) 81 kcal preterm formula.

POPULATION: A total of 109 survivors whose <1000 g birth weight was appropriate for gestational age. Mean gestational age was 25.8 weeks.

RESULTS: Graphs were constructed for weight, length, and head circumference by week of age. Mean and +/- 2 SD lines were depicted, with mean intrauterine growth lines for comparison. Separate graphs showed mean weight, length, and head circumference growth by 100 g birth weight cohorts. Mean Z scores based on normal intrauterine growth curves were calculated. Weight Z scores were -.35 at birth, -1.79 at 14 days, and -1.87 at 56 days. Length Z scores were -.32 at birth, -1.29 at 14 days, and -2.24 at 56 days. Head circumference Z scores were 0.01 at birth, -1.26 at 14 days, and -1.06 at 56 days. (Z score = [measured parameter - intrauterine mean for gestation]/intrauterine SD for gestation). Repeated-measures multivariate ANOVAs showed the following significant Z score changes. There were decreases in Z scores for weight, length, and head circumference between birth and 14 days and an additional decrease for length between 14 and 56 days. Head circumference Z scores increased from day 14 to day 56, but remained smaller at day 56 than at day 0. Initially, head circumference Z scores were better than weight or length (possibly because of late head measurement timing). At day 14, the Z scores for weight were lower than those for length and head circumference. At day 56, the head circumference Z scores were higher than those for length or weight.

CONCLUSION: Compared with intrauterine standards, weight, length, and head circumference were all worse at day 56 than at birth, although there was relative head-sparing and weight growth paralleled intrauterine growth after 14 days. Length worsened from day 14 to day 56 in spite of the use of calcium and phosphorus-enriched formula.