Analysis of Abnormal Chromosomal Karyotypes in Fetal Cord Blood of 58 Fetuses

To analyze the abnormal chromosomal karyotypes in fetal cord blood samples, and to investigate the relationship between the indications of prenatal diagnosis and the types of abnormal karyotypes. Cordocentesis were performed in 1 200 pregnant women with the indications of prenatal diagnosis during 17～38 gestational weeks. The samples of fetal blood were taken and chromosomal karyotypes were analyzed. 58 abnormal chromosomal karyotypes were found and the abnormal rate was 4 8%(58/1 200). Trisomy was the main abnormal karyotype which was 55%(32/58) in all abnormal cases. Trisomy 21 was 33%(19/58). 11 case (19%) with abnormal ultrasound findings were found to have abnormal karyotypes. There were 10 cases of balanced translocation (17%) and 8 cases of inversion. The indications for prenatal diagnosis were as following: advanced maternal age (31%, 18/58), balanced translocation in parents (26%, 15/58), intrauterine growth retardation (IUGR) (12%, 7/58), abnormal value of pregnancy associated with plasma protein A (PAPP A)(14%, 8/58). [Conclusion] Trisomy, especially trisomy 21 is the most frequent abnormal chromosomal karyotype in fetuses. In the pregnant women with prenatal diagnosis, abnormal karyotypes in fetuses are found to be higher in the following situations: advanced maternal age, balanced translocation, abnormal findings by ultrasound, IUGR, and abnormal value of PAPP A.