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.