孕妇外周血中胎儿有核红细胞的出现频率及其与孕周的关系

目的 探讨用检测孕妇外周血中的胎儿有核红细胞（ＮＲＢＣ）进行无创性产前诊断的最佳时间。方法 对４４名孕龄６～４０周的孕妇外周血进行不连续密度梯度离心，将分离后的细胞进行制片，显微镜下行有核红细胞计数，然后用显微操作法一一获取，进行Ｙ染色体特异性ＤＹＺ１基因的聚合酶链反应（ＰＣＲ），以确定其胎儿来源。结果 ４４名孕妇中有１７例其外周血中检出有ＮＲＢＣ，分布于妊娠第９～２６周，其中以妊娠第１１～２０周

Fetal Nucleated Red Blood Cell in Maternal Peripheral Blood: Frequency and Relationship with Gestational Age

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.