Pronounced growth restriction (GR) occurs after very preterm birth. The interaction between IGF-I, nutritional intake, and growth was evaluated prospectively in 64 infants with a mean (SD) GA of 25.7 (1.9) wk. Blood sampling of IGF-I and measurements of weight, length, and head circumference were performed weekly until discharge. Daily calculation of nutritional intake was performed. Standard deviation scores (SDSs) for growth parameters defined two growth phases: GR phase (birth until lowest SDS) and catch-up (CU) phase (lowest SDS until 35 gestational weeks). IGF-I concentrations during the first postnatal weeks were low and increased at 30 wk GA, irrespective of GA at birth, coinciding with initiation of CU growth. Concentrations of IGF-I were positively associated with change in weight SDS during the GR phase, p ϭ 0.001 and CU phase, p ϭ 0.004 -0.027. Protein and energy intake were not associated with change in SDS weight during the GR phase as opposed to the CU phase (p Ͻ 0.001, respectively). Nutritional intake did not correlate to concentrations of IGF-I before 30 wk GA. IGF-I is associated with growth at an earlier postnatal age than nutrient intake and the effect of nutrition on levels of IGF-I may be restricted to the period of established CU growth. T he maximum growth rate of the fetus is reached in the middle of pregnancy, where it is approximately three times higher than at term (1). Fetal growth rate is to a large extent determined by placental capacity of delivering nutrients to the fetus, whereas genetic influence seems to play a less important role. Placental function depends on the maternal nutritional state and the intrauterine endocrine environment. At preterm birth, the fetal-placental interaction is interrupted, which has an impact on continued extrauterine growth capacity. Postnatal growth retardation occurs almost inevitably after preterm birth and has been associated with decreased brain volumes and impaired neurodevelopmental outcome (2,3). Although attempts are made to optimize postnatal nutritional intakes in preterm infants, these are still commonly suboptimal according to intrauterine requirements (4). Increased postnatal nutritional intake has been shown to improve growth rate in very LBW infants (5), although a recent study could not demonstrate any apparent effect of hyperalimentation on subsequent postnatal growth in very preterm infants (6).IGF-I is an important fetal growth factor, which is essential for the developing brain (7). Concentrations of fetal IGF-I are closely related to placental transfer of glucose where fetal glucose increases insulin secretion, which in turn stimulates fetal IGF-I production (8). Fetal levels of IGF-I may also be regulated by an interaction at the feto-maternal placental interface (9). The disruption of placental nutrient supply after birth is followed by a rapid decrease in postnatal levels of IGF-I, suggesting a low endogenous production (10). While term infants restore their IGF-I levels within the first postnatal weeks, very prete...
Protein analyses of the milk before individual fortification provides a new tool for an individualized feeding system of the preterm infant. The bovine whey protein fortifier attained biochemical and growth results similar to those found in infants fed human milk protein exclusively with the corresponding protein intakes.
ABSTRACT. In a double-blind, randomized study, 28 healthy, growing very low birth wt, appropriate-for-gestational-age infants were fed human milk, preferably mother's own, fortified daily with human milk protein and/or human milk fat. The infants entered the study when they were stable on complete enteral intakes of 170 mL/kg/d (mean age = 19 d). The study lasted for a mean of 4 wk.Samples from all the milks were collected daily, and intakes of protein, fat, carbohydrates, energy, and electrolytes were calculated weekly during the whole study period.Protein intakes ranged from 1.7 to 3.9 g/kg/d, and energy intakes from 100 to 150 kcal/kg/d. Wt and length gain in the nonprotein-enriched groups were 15.6 + 2.7 g/kg/d (mean + SD) and 0.88 + 0.17 cm/wk; the corresponding figures for the protein-enriched groups were 20.2 + 2.1 g/ kg/d and 1.24 & 0.14 crnlwk. There was a strong correlation between protein intake and growth in wt and length up to an intake of about 3 g/kg/d; more protein did not result in increased growth. The same was true for energy intake, with a maximal growth rate a t an intake of about 120 kcal/ kg/d. A protein intake of more than 3 g/kg/d resulted in a growth rate equal to or higher than the estimated intrauterine growth rate. Some infants fed mature banked human milk alone had a poor growth. Sodium intake was low, ranging from 1.5 to 2.6 mmol/kg/d. No correlation was found between sodium intake and growth rates.
Routines for breastmilk handling differ among the 36 neonatal units in Sweden. New guidelines can standardize the handling of human milk, thereby improving nutrition and minimizing the risk of breastmilk-induced infection in the preterm infant.
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