Reduced renal length and volume 20 years after very preterm birth

Intrauterine growth retardation is presumed to be associated with decreased renal size and impaired renal function as a result of stunted kidney development and nephron deficit. To study whether very preterm birth also affects renal size at young adulthood, we sonographically measured bipolar kidney length and volume in 51 very premature individuals (<32 weeks of gestation), either small (SGA) or appropriate (AGA) for gestational age (22 SGA and 29 AGA), and 30 full-term controls 20 years after birth. Relative kidney length and volume were calculated. Both absolute and relative left kidney length and volume were significantly lower in SGA and AGA individuals, notably in women. Renal size did not differ between SGA and AGA individuals. In 70% of controls, the left kidney was larger than the right one compared with 40.9% in SGA [relative risk (RR) 1.7; 95% confidence interval (CI) 1.0−3.0] and 48.3% in AGA (RR 1.5; 95% CI 0.9−2.3) individuals. Renal structural anomalies were present in eight prematurely born participants only. Our data suggest that kidney growth is stunted after preterm birth, especially on the left side, and in the female gender

Preterm neonates with nephrocalcinosis:natural course and renal function

The aim of the study was to evaluate the natural course of nephrocalcinosis (NC) in preterm neonates and the effect of NC on blood pressure and renal glomerular and tubular function. In a prospective observational study of 201 preterm neonates (gestational ag

Is nephrocalcinosis in preterm neonates harmful for long-term blood pressure and renal function?

OBJECTIVE. The aim of our study was to examine long-term effects of nephrocalcinosis in prematurely born children. PATIENTS AND METHODS. Preterm neonates (gestational age < 32 weeks) with (n=42) and without (n=32) nephrocalcinosis were prospectively studied at a mean age of 7.5 (+/- 1.0) years. RESULTS. Blood pressure did not differ in ex- preterm infants with and without nephrocalcinosis but was significantly higher than expected for healthy children. In comparison to healthy children, more ex- preterm infants with neonatal nephrocalcinosis had (mild) chronic renal insufficiency (glomerular filtration rate: < 85 mL/ min per 1.73 m(2); 6 of 40); this is in contrast to ex- preterm infants without neonatal nephrocalcinosis (2 of 32). Tubular phosphate reabsorption and plasma bicarbonate were significantly lower in children with nephrocalcinosis compared with children without nephrocalcinosis. In addition, more ex- preterm infants with and without nephrocalcinosis than expected had low values for plasma bicarbonate and early- morning urine osmolality compared with healthy children. Kidney length of ex- preterm infants with and without nephrocalcinosis was significantly smaller than expected in healthy children of the same height. Nephrocalcinosis persisted long- term in 4 of 42 children but was not related to blood pressure, kidney length, or renal function. CONCLUSIONS. Nephrocalcinosis in preterm neonates can have long- term sequelae for glomerular and tubular function. Furthermore, prematurity per se is associated with high blood pressure, relatively small kidneys, and (distal) tubular dysfunction. Long-term follow-up of blood pressure and renal glomerular and tubular function of preterm neonates, especially with neonatal nephrocalcinosis, seems warranted