目的探讨中、晚孕期超声筛查21-三体综合征的价值和局限性。方法在妊娠中期和中晚期分别对有产前诊断指征的3110和187名孕妇行羊膜腔和脐带穿刺术,检查染色体核型,比较不同穿刺指征孕妇的21-三体检出率,并分析21-三体与超声异常的关系。结果接受羊膜腔穿刺的3110名孕妇中,检出21-三体41名,检出率1.32%,3110名孕妇中超声异常98名,检出21-三体6名,检出率6.12%。超声异常者21-三体检出率(6.12%)明显高于唐氏综合征高危者(0.98%)、单纯高龄孕妇(0.58%,P<0.05)。187名脐血染色体核型分析,检出21-三体9胎,检出率4.81%,187名孕妇中超声异常128名,检出21-三体5胎,检出率3.91%。结论中、晚孕期超声筛查21-三体综合征既有很大的价值,也存在局限性。 Objective To investigate the value and limitations of ultrasound screening for 21-trisomy syndrome in middle and late pregnancy. Methods 3110 and 187 pregnant women with indications of prenatal diagnosis of amniocentesis and umbilical cord punctures were performed in the second and third trimester of pregnancy. The chromosome karyotypes were examined. The detection rate of 21-trisomy in pregnant women with different puncture indications was compared and analyzed 21-trisomy and ultrasound abnormalities. Results Of the 3110 pregnant women receiving amniocentesis, 41 were detected in 21-trisomy, the detection rate was 1.32%. Among 3110 pregnant women, 98 were ultrasonographic abnormalities and 6 were detected in 21-trisomy. The detection rate was 6.12%. The detection rate of 21- trisomy (6.12%) in abnormal ultrasound was significantly higher than that in Down’s syndrome (0.98%), simple elderly pregnant women (0.58%, P <0.05). 187 karyotypes of umbilical cord blood were detected. Twenty-one trisomy 9 fetuses were detected, the detection rate was 4.81%. Among the 187 pregnant women, there were 128 abnormalities in ultrasound. Twenty-one trisomy 5 fetuses were detected and the detection rate was 3.91%. Conclusion In the middle and late stages of ultrasound screening for 21-trisomy syndrome has great value, there are also limitations.