Atrial natriuretic factor concentration in normal, growth-retarded, anemic, and hydropic fetuses.

Abstract

Our purpose was to establish a reference range with gestation for plasma concentrations of atrial natriuretic factor in fetal blood and to examine whether the concentration is altered in fetal anemia, acidemia, or hydrops. Atrial natriuretic factor was measured in umbilical venous blood taken by cordocentesis from pregnancies complicated by red blood cell isoimmunization (n = 17), intrauterine growth retardation (n = 12), and hydrops fetalis (n = 20) and from controls (n = 66). Additionally, maternal blood atrial natriuretic factor concentration was measured in 40 uncomplicated pregnancies. In the control group detectable levels were found from 16 weeks onward, and the fetal plasma atrial natriuretic factor concentration did not change with gestation. In anemic, acidemic, and hydropic fetuses the concentration was higher than in controls. Fetuses are capable of producing atrial natriuretic factor under physiologic conditions, and the concentration is increased appropriately in pathologic states.