妊娠中、晚期300例胎儿脐血染色体核型分析

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

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,抽脐血查染色体核型。结果 发现异常核型23例(77%),其中妊娠中期检出异常86%(15174);妊娠晚期63%(8126),P=0.77。三体为主要的染色体异常,占异常核型的609%(1423)。其中21三体占391%(923),平衡易位次之,占217%(523)。高龄孕妇21三体儿的检出率为54%(592);非高龄组19%(4208),P=0.26。胎儿宫内发育迟缓(intrauterinegrowthretardation,IUGR)组异常核型检出率高达263%(519)。平衡易位组为385%(513)。结论 在有产前诊断指征的孕妇,胎儿染色体异常的发生率为77%,染色体三体、尤其21三体是妊娠中、晚期主要的异常核型,是高龄以及IUGR最常见的染色体异常。

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.