RENAL-FUNCTION IN VERY-LOW-BIRTH-WEIGHT INFANTS - NORMAL MATURITY REACHED DURING EARLY-CHILDHOOD

Development of glomerular and tubular renal function is delayed in preterm infants. To study the pattern of maturation during infancy and childhood, we reevaluated renal function in 22 very low birth weight infants-in 14 of the infants at 18 months postconceptional age (9 months corrected age) and in the remaining 8 infants ot 8 years of age. The glomerular filtration rote remained lower of 9 months corrected age than in term infants of the same postconceptional age: 82 +/- 23 versus 125 +/- 18 ml/min per 1.73 m2 (p < 0.001). At 8 years of age the glomerular filtration rote did not differ from that of healthy control subjects. Effective renal plasma flow, filtration fraction, albumin excretion, maximal concentrating ability, and kidney size determined by ultrasonography were all normol at 8 years of age. We conclude that renal function, which is markedly reduced during the neonatal period in very low birth weight infants, reaches normol maturity by 8 years of age but not by 9 months corrected age.