RENAL FUNCTION AS A MARKER OF HUMAN FETAL MATURATION

Abstract

Sixty clinically well infants of various gestational ages (27-40 wk) were studied from 24-40 h after birth to evaluate glomerular filtration rate and renal excretion rate of Na at various stages of fetal maturation. Creatinine clearance was directly related to gestational age (r = 0.643). Fractional Na excretion was inversely related to gestational age (r = -0.755). The renal functions of small for gestational age infants were similar to those of full-term infants whose birth weights were appropriate for gestational age. The glomerular functions of an infant < 32 wk of gestation were more predominant than the tubular function resulting in a greater fractional Na excretion rate and higher urinary Na loss in infants of this gestational age, when compared with the more mature infants.