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

Abstract

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.

Keywords: Air displacement plethysmography; Body composition; Fat mass; Fat-free mass; Preterm infants.