The serum transferrin receptor concentration in seven fetuses with hemolytic disease

Six pregnant women who received intrauterine transfusions and their seven f etuses were followed during gestation. Hemoglobin concentration hematocrit value serum ferritin, and serum transferrin receptor (TfR) concentrations w ere measured. In the fetal samples, there was a tendency for the TfR concen tration to decrease during gestation and after the intrauterine transfusion s. Serum TfR values varied between 0.7 and 5.2 mg/L, which is near the post natal level measured in premature infants. On the contrary, one would have expected to find highly elevated values due to the active fetal erythropoie sis. The fetal regulation of TfR production may differ from that described postnatally.