BIOELECTRICAL-IMPEDANCE ANALYSIS IN SMALL AND APPROPRIATE-FOR-GESTATIONAL-AGE NEWBORN-INFANTS

Objective: To determine the reliability of bioelectrical impedance ana lysis, and to compare and contrast the anthropometric and BIA status o f newborns. Design: BIA and anthropometric parameters were compared in the few days after birth and at about 3 weeks of age. Setting: At the maternity hospital or in a paediatric care unit. Subjects: Small- or appropriate-for-gestational-age newborns, with birth weight below or a bove the 10th percentile of the reference value, respectively. Measure ments were performed on 36 and 47 newborns at birth, and for a subgrou p (21 and 11) again about 3 weeks later, respectively. Results: At bir th, length2/resistance was 4.3 +/- 0.6 and 6.1 +/- 1.2 cm2/OMEGA (p= 1 0(-7)), and at 3 weeks of age length2/resistance was 5.0 +/- 0.6 and 5 .7 +/- 0.8 cm2/OMEGA (P = 0.11), for small- and appropriate-for-gestat ional-age newborns, respectively. Percentage reliability was 2.2% and 2.6% for intra- and inter-observer measurements of resistance. Importa nce of a correct placement of the sensor electrode was demonstrated. C onclusions: Ease of measurement and reliability of BIA in neonates wer e shown. Evolution of BIA values is in agreement with the known increa se in total body water linked to regrowth of cell mass in small-for-ge stational-age infants. Additional study is required before BIA should be used in usual clinical setting in newborns due to the lack of predi ction equation.