Fetal Nucleated Red Blood Cell in Maternal Peripheral Blood: Frequency and Relationship with Gestational Age / 中华围产医学杂志

ABSTRACT

Objective To study the frequency and relationship with gestational age of fetal nucleated red blood cell (NRBC) in maternal peripheral blood. Methods Samples of peripheral blood in 44 women of 6~40 gestational weeks were collected to enrich the fetal nucleated red blood cells by discontinuous density gradient centrifugation. The isolated cells were made smears and counted under the microscope. NRBCs were found and retrieved using a micromanipulator under a microscope for PCR amplification of Y chromosome specific DNA to determine fetal sex. Results NRBCs were found in 17 out of 44 maternal samples, distributing from 9 to 26 gestational weeks The highest frequency of NRBC was found in 11~20 gestational age which reached to 76.5%(13/17). The amount of detected NRBCs ranged from 5/7ml to 30/7ml. Y chromosome 149bp was found in 7 cases and not in the other 10, which agreed to the actual fetal sexes. Conclusion The appropriate time to make a prenatal diagnosis using fetal nucleated red blood cells is in 11~20 gestational age.