Fetal hematology.

The objective of this study was to establish normal fetal hematological parameters throughout gestation. Samples of pure fetal blood from 35 fetuses of 21-38 weeks' gestation were obtained by fetal blood sampling under continuous ultrasound guidance. The hematological parameters were determined with automated cell counter within 30 minutes after the procedures. Fetal red blood cell and granulocyte counts rose significantly with advancing gestation, whereas, the mean corpuscular volume fell. There were no significant changes in fetal hemoglobin, hematocrit, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, red cell distribution width, total white blood cell count, lymphocyte count, mid-cell count, platelet count, mean platelet volume, and platelet distribution width with increasing gestation. The growing application of fetal blood sampling to the prenatal diagnosis renders mandatory a knowledge of normal fetal blood values. These results may provide useful reference values for prenatal diagnoses of hematological disorders.