Effect of intrauterine growth retardation on renal function on day one of life.

We measured inulin clearance per kilogram, fractional sodium excretion per kilogram, osmolality, and urinary prostaglandin concentration in seven growth-retarded neonates and six appropriately grown neonates matched for gestational age during the first 24 hours of life to determine the effect of fetal growth retardation on renal function. There was a nonsignificant reduction in inulin clearance per kilogram in the growth-retarded neonates (p = 0.11). Inulin clearance correlated with gestational age in both groups. It was significantly correlated with birthweight in the growth-retarded group (p less than 0.05) but did not reach significance in the control group (p less than 0.06). Fractional sodium excretion was significantly higher in the growth-retarded fetuses (p less than 0.05). This increase was not explainable by differences in mean blood pressure and intravenous fluid intake, although differences in urinary prostaglandin concentrations during the study interval may be involved. In conclusion, we have demonstrated that growth retardation is associated with impaired renal maturation, which during the first 24 hours of life is manifest as decreased glomerular filtration rate and increased sodium excretion.