Assessment of Body Composition Using Bioelectrical Impedance Analysis in Preterm Neonates Receiving Intensive Care.

AIM Evaluation of bioelectrical impedance values and body composition during early infancy in groups of preterm newborns and full-term newborns. MATERIAL AND METHODS A total of 38 newborns was enrolled in the study: 26 very low birth weight preterm newborns with the mean birth weight of 1236 g (SD: 161) as the study group and 12 term newborns with birth weight of 2500-4000 g as the control group. Anthropometric measurements and body composition using bioimpedance analysis at the age of 1 week and at the age of 3 months were assessed. RESULTS At the age of 1 week we noted higher resistance with the impedance variables R5, R50 R100 in the group of preterm newborns compared to the full-term newborns' group (923(144) vs. 647(78) p < 0.01; 870 (140) vs. 615 (73) p < 0.01; 844 (141) vs. 599 (72) p < 0.01). Moreover, the bioimpedance index and fat mass (%) were significantly lower in the group of preterm infants at the age of 3 months (3.81 (0.9) vs. 5.72 (1.1) p < 0.01; 16.1% (1.7) vs. 18.9% (2.7) p = 0.006). We observed a decreased amount of the percentage of total body water (TBW%) in both of the analyzed infant groups throughout the observational period. At the age of 3 months the amount of TBW % was similar in both groups (71.5% (7.03) vs. 70.8% (8.8) p = 0.8). CONCLUSIONS Bioimpedance analysis is a simple, non-invasive, repeatable method to estimate total body water, fat-free mass, and fat mass, both in term and preterm newborns. The study confirms differences in body composition between preterm newborns and full-term newborns. Moreover, we have shown that the differences are present until the end of the 3rd month of life, with the exception of the amount of water percentage (TBW %), which are similar in both groups.