Beyond the scale: Bioelectrical Impedance for Neonatal Growth

Abstract

Optimising growth in very preterm and very low birth weight infants remains a central challenge in neonatal care, requiring clinical decisions that balance survival, maturation, and long-term developmental outcomes. Growth in this vulnerable population is traditionally assessed using anthropometric measures, such as body weight and length. However, this offers limited insight into the underlying changes in body composition that accompany early postnatal adaptation and clinical interventions. Bioelectrical impedance analysis (BIA) is a promising alternative, providing a low cost, minimally invasive approach that is well suited to the neonatal intensive care unit (NICU) and enables repeated, longitudinal assessment of body composition.1 By capturing dynamic changes in fat mass (FM) and fat-free mass (FFM), BIA offers an opportunity to improve understanding of how treatments such as corticosteroids, alongside nutrition and other therapeutic exposures, shape neonatal growth trajectories in very preterm and very low birth weight infants, beyond what can be inferred from size-based measures alone.