ERYTHROPOIETIN CONCENTRATIONS IN AMNIOTIC-FLUID AND UMBILICAL VENOUS-BLOOD FROM RH-IMMUNIZED PREGNANCIES

We set out to investigate prospectively the levels of erythropoetin in amniotic fluid and umbilical venous blood, and to attempt to relate t hese to fetal haemoglobin and lactate concentrations and to PCO2 and P O2 in Rh immunised patients studied before the onset of labor. Fetal b lood was obtained by cordocentesis, and amniotic fluid by amniocentesi s from a consecutive series of 36 Rh immunized patients at the time of fetal blood sampling. There was a close correlation (tau = 0.357, P = 0.0001) between the concentrations of erythropoietin in umbilical ven ous blood and those in amniotic fluid. Erythropoietin in umbilical ven ous blood correlated inversely with hemoglobin (tau = 0.453, P = 0.000 1), and directly with lactate concentrations (tau = 0.450, P = 0.0005) . When all other variables were considered, multiple regression analys is demonstrated hemoglobin concentration to be the only variable to be related to the level of erythropoietin in umbilical venous blood take n before transfusion. When the same analysis was performed on the same variables, adding erythropoietin concentration in amniotic fluid as t he dependent variable, only erythropoietin in umbilical venous blood w as found to be related to the level of erythropoietin in amniotic flui d. We conclude that the erythropoietin concentration in umbilical veno us blood from Rh-immunized patients before the onset of labor, is rela ted to fetal anemia. We also conclude that erythropoietin concentratio n in amniotic fluid is related to that in fetal blood, thereby indicat ing that the fetus is an important source of amniotic fluid erythropoi etin in non laboring patients.