Neonatal Renal Ultrasound Reference Values in Romanian Term Newborns: Correlations with Anthropometric Characteristics.

Background: The establishment of population-specific reference values for neonatal renal dimensions is essential for accurate assessment of kidney development. Currently, standardized reference data for renal volume in Romanian newborns are lacking. This study aims to establish normal renal dimensions and volumes in Romanian term newborns and evaluate their correlations with anthropometric characteristics.

Methods: A prospective study was conducted at Polizu Maternity, Bucharest, Romania, involving a cohort of 100 term newborns with a gestational age (GA) between 37 and 42 weeks, all delivered at the INSMC "Alessandrescu-Rusescu" Polizu Maternity Hospital. Routine renal ultrasound was performed for all term newborns within the first 72 h of life. Renal dimensions were measured in the longitudinal and axial sections, and the volume was calculated.

Results: The average kidney dimensions were as follows: length 42.0 ± 3.4 mm, width 22.6 ± 2.6 mm, and thickness 19.9 ± 2.5 mm. Renal volume ranged from 5.1 to 18.9 mL, with an average of 10.2 ± 2.5 mL. The kidney volume was significantly correlated with gestational age (r = 0.195; p = 0.05) and birth length (r = 0.267; p = 0.008), and most strongly with birth weight (r = 0.306; p = 0.002).

Conclusions: This study provides the first reference values for renal dimensions in Romanian term newborns. Renal volume shows modest correlations with anthropometric characteristics, particularly birth weight. These reference values may serve as baseline measurements for future longitudinal studies investigating renal development and disease risk.