Body composition in late preterm infants in the first 10 days of life and at full term.

AIM: To investigate changes in body weight, fat-free mass, fat mass and percentage of body fat during early life and at full-term postconceptional age (PCA) in preterm infants born after 32 gestational weeks and before 37. METHODS: Twenty-nine late preterm infants underwent growth and body composition assessment by air displacement plethysmography (ADP) at the age of 4 days and at full-term PCA. In 25 of these infants, body composition was assessed three times between days four and nine of life. The preterm infants were compared with 29 full-term infants, matched for gestational age, sex and body weight. RESULTS: There was a significant increase in birth weight and fat-free mass between days four and nine of life. Preterm infants had significantly more body fat 382 ± 180 g vs 287 ± 160 g than full-term infants at full-term PCA. Preterm infants showed poor linear growth between birth and full-term PCA. CONCLUSION: Weight gain after the initial postnatal weight loss consists of gain in fat-free mass. At full-term PCA, preterm infants were stunted. When compared with full-term new born infants matched for body weight and gestational age, preterm infants had more body fat and a higher percentage of body fat.

Different feeding regimens were not associated with variation in body composition in preterm infants.

AIM: The aim was to determine body composition and growth in preterm infants based on two different feeding regimens and to assess how standard and individual fortification (IF) affect energy and protein intake. Body composition was assessed at full term and at four months corrected age. METHODS: Sixty preterm infants born before gestational week 32 were randomized either to IF of mother's breast milk after it had been analyzed or to standard fortification (SF) of mother's breast milk based on the average protein and energy content of breast milk. Body composition was measured at full term and at four months corrected age, using air displacement plethysmography. Growth rate and nutritional intake analyses were also conducted. RESULTS: At 40 weeks gestational age, there was no difference between weight (g) (IF 3056 ± 472 vs. SF 3119 ± 564), body fat (%) (IF 19 ± 3.3 vs. SF 21 ± 5.6), fat mass, or fat-free mass between the two groups. Furthermore, there was no difference between the groups in weight, length, head circumference, or body composition at four months corrected age. CONCLUSIONS: Fortification based on breast milk analysis may not improve growth in preterm infants compared to SF. However, both groups were smaller and had a different body composition at term corrected age compared to infants born at term.

Body composition and growth in full-term small for gestational age and large for gestational age Swedish infants assessed with air displacement plethysmography at birth and at 3-4 months of age.

BACKGROUND: Being born small for gestational age (SGA) or large for gestational age (LGA) has short and long term metabolic consequences. There is a growing interest in the extent to which body composition, both in the short and the long term, differs in infants born at the extremes of these birth weights. METHODS: Body composition in 25 SGA and 25 LGA infants were assessed during the first days of life and at 3-4 months of age using air displacement plethysmography. RESULTS: SGA infants had significantly lower body fat (%) at birth compared to LGA infants. SGA infants increased their body weight and length at a significantly higher rate between birth and 3-4 months than LGA infants. Fat mass (g) in SGA infants increased 23 times between birth and 3-4 months of age compared to 2.8 times for LGA infants. At 3-4 months of age LGA infants reached a threshold in body fat (%) while SGA infants were still gaining body fat (%). CONCLUSION: Several significant differences have been identified between SGA and LGA infants, indicating that the effects of intrauterine life continues to play an important role in body composition and growth during the first 3-4 months of life.

An Evaluation of the Pea Pod System for Assessing Body Composition of Moderately Premature Infants.

(1) BACKGROUND: Assessing the quality of growth in premature infants is important in order to be able to provide them with optimal nutrition. The Pea Pod device, based on air displacement plethysmography, is able to assess body composition of infants. However, this method has not been sufficiently evaluated in premature infants; (2) METHODS: In 14 infants in an age range of 3-7 days, born after 32-35 completed weeks of gestation, body weight, body volume, fat-free mass density (predicted by the Pea Pod software), and total body water (isotope dilution) were assessed. Reference estimates of fat-free mass density and body composition were obtained using a three-component model; (3) RESULTS: Fat-free mass density values, predicted using Pea Pod, were biased but not significantly (p > 0.05) different from reference estimates. Body fat (%), assessed using Pea Pod, was not significantly different from reference estimates. The biological variability of fat-free mass density was 0.55% of the average value (1.0627 g/mL); (4) CONCLUSION: The results indicate that the Pea Pod system is accurate for groups of newborn, moderately premature infants. However, more studies where this system is used for premature infants are needed, and we provide suggestions regarding how to develop this area.