Serial assessment of fat and fat-free mass accretion in very preterm infants: a randomized trial.

BACKGROUND Clinicians could modify dietary interventions during early infancy by monitoring fat and fat-free mass accretion in very preterm infants. METHODS Preterm infants were randomly assigned to either having reports on infant body composition available to the clinicians caring for them (intervention group) or not having reports available (control group). All infants underwent serial assessments of body composition by air-displacement plethysmography before 32 weeks of postmenstrual age (PMA) and at 36 weeks PMA. The primary outcome was percent body fat (%BF) at 3 months of corrected age (CA). RESULTS Fifty infants were randomized (median gestational age: 30 weeks; mean ± SD birth weight: 1387 ± 283 g). The mean %BF increased from 7 ± 4 before 32 weeks PMA to 20 ± 5 at 3 months CA. The differences in mean %BF between the intervention group and the control group were not statistically significant at 36 weeks PMA (14.5 vs. 13.6) or 3 months CA (20.8 vs. 19.4). Feeding practices and anthropometric measurements during hospitalization did not differ between groups. CONCLUSIONS Serial assessments of body composition in both intervention and control groups showed consistent increments in %BF. However, providing this information to clinicians did not influence nutritional practices or growth. IMPACT Serial assessments of body composition in preterm infants at 32 and 36 weeks postmenstrual age show consistent increments in % body fat up to 3 months of corrected age.However, providing this information to the clinician did not influence nutritional practices or growth.