妊娠中、晚期300例胎儿脐血染色体核型分析

目的 分析妊娠中、晚期胎儿脐血染色体核型，了解该时期异常核型出现的频率、类型及与各种产前诊断指征的关系。方法 ３００例有产前诊断指征的孕妇，在妊娠１８～３８孕周时穿刺胎儿脐带血管，帛脐箅查染色体核型。结果 发现异常核型２３例（７．７％），其中２１三体占３９．１％（８／１２６），Ｐ＝０．７７。三体为主要的染色体异常，占异常核型的６０．９％（１４／２３）。其中２１三体占３９．１％（９／２３），平衡易位

Analysis of chromosomal karyotypes in 300 fetal blood samples during the second and third trimesters of gestation

Objective To analyze the fetal chromosomal karyotypes from the blood samples obtained by cordocenteses during the second and third trimesters, and to investigate the types of chromosomal abnormalities, as well as the relationship between the abnormal karyotypes and the indications of prenatal diagnosis.Methods Cordocenteses were performed in 300 pergnant women with different indications for prenatal diagnosis during the 18 to 38 gestational weeks, and fetal chromosomal karyotypes were examined.Results Twenty three chromosomal abnormalities(7.7%) were checked out. In the second trimester, there were 15 abnormalities in 174 samples (8.6%); whereas in the third trimester, it was 8 out of 126(6.3%), P=0.77 . Trisomy, the leading abnormality, consisted of 60.9%(14/23) of all abnormalities and 9 out of 14 were trisomy 21, which was 39.1%(9/23). In those aged over 35 years, trisomy 21 was detected in 5 of 92(5.4%), and in the age under 35 years, it was 4 out of 208(1.9%), P =0.26. Thirty three women had the history of giving a birth of trisomy 21 previously, this time, however, no one was recurrent.Highest chromosomal aberration rate, 26.3%(5/19),was detected in the fetuses with intrauterine growth retardation(IUGR), and all were trisomy. Balanced translocation was found in 5 fetuses (1 associated with Robertsonian translocation), which was 21.7%(5/23).Conclusion During the second and third trimesters, the rate of chromosomal abnormality is 7.7% in those fetuses who have maternal indications for prenatal diagnosis. Trisomy, especially trisomy 21, is the most common abnormal karyotype found in these periods and in advanced maternal age,as well as in severe IUGR.