Clinical Analysis of 336 Cases of Prenatal Diagnosis of Fetal Chromosomal Karyotypes of Cording Blood

Objective To investigate the indications of prenatal diagnosis,common types of the abnormal karyotypes during the second and third trimesters,and to assess the effectiveness of cordocentesis in the prenatal diagnosis.Methods Cordocentesis were performed on 336 pregnant women with different indications of prenatal diagnosis during their 18 to 36 gestational weeks.Fetal chromosomal karyotypes were also examined,and analysed relations between abnormal karyotype and the indications of prenatal diagnosis.Results 48 chromosomal abnormalities(14.3%) were detected.Trisomy,the main abnormality,accounted for 62.5%(30/48) of all abnormalities;there were 12 with trisomy 18,8 with trisomy 21,8 with trisomy 13,and 2 with trisomy 22.The highest trisomy chromosomal aberration rate(26.7%) was detected in the fetuses with multiple abnormalities and minor fetus anatomical abnormalities significantly increase the detectable rate of trisomy 21.Conclusion Fetal abnormalities were the main indications for prenatal diagnosis.Trisomy is the main type of chromosomal karyotype malformation during the second and third trimesters of pregnancy,and cordocentesis is an important technique for prenatal diagnosis during this period.Ultrasonographic prenatal screening offers access to find fetal chromosomal abnormalities.