Assessment of renal function and renal morphology in preterms and term newborns

Abstract

Objective To explore the relationship between renal volume and function in the preterm and term newborns at different gestational ages. Methods This study was conducted at the First Affiliated Hospital of Zhengzhou University from October 2016 to March 2018.A total of 626 newborns with different gestational ages were included and the renal volume was determined by ultrasonography.Blood samples were taken for laboratory tests to detect renal function including urea, creatinine, uric acid and estimated glomerular filtration rate. Results A total of 352 preterm and 274 full term newborns were enrolled at birth.The mean gestational age of the neonates was (36.0±3.5) weeks and the mean birth weight was (2.59±0.77) kg.The mean renal volume of the preterm infants was (19.57±4.30) cm3 and estimated glomerular filtration was (21.68±5.99) mL/(min·1.73 m2); the mean renal volume of the term infants was(23.03±3.80) cm3 and estimated glomerular filtration was(46.60±10.21) mL/(min·1.73 m2). The renal volume and estimated glomerular filtration of term infants was significantly greater compared to the preterm infants(t=12.96, 33.10, all P<0.001). The renal volume was highly linear positively correlated with gestational age, birth weight and birth length(r=0.546, 0.605, 0.592, all P<0.001). The renal volume was highly linear positively correlated with estimated glomerular filtration(r=0.396, P<0.001). The renal volume was negatively correlated with urea, creatinine and uric acid(r=-0.210, -0.280, -0.176, all P<0.001). Conclusions The renal volume increases with gestational age and birth weight in neonates.Estimated glomerular filtration increases with renal volume in neonates.The preterm infants have immaturity kidney size and poor development so that they need special medical care. Key words: Early newborn; Infant, preterm; Infant term; Renal volume; Renal function; Estimated glomerular filtration