早孕期胎儿颈项透明层厚度与绒毛染色体G显带核型的关系

The relationship between chorionic villus karyotype analysis and fetal nuchal translucency thickening at 1st trimester ultrasound examination

目的探讨早孕期胎儿颈项透明层厚度(NT)测量与绒毛染色体核型分析联合应用的临床价值。方法回顾性分析120例早孕期行绒毛染色体核型分析的孕妇,研究其胎儿NT值与染色体核型及妊娠结局的关系。结果 120例病例中胎儿NT≤2.5 mm 76例,未检出异常核型(0%);NT≥2.5 mm 44例,异常核型9例(20.45%)。其中,25例2.5mm≤NT≤3.5 mm的胎儿检出染色体异常1例,检出率为4%(1/25);19例NT≥3.5mm的胎儿检出染色体异常8例,检出率为42.11%(8/19),两组异常核型检出率的差异有统计学意义(P<0.05)。根据NT增厚程度的不同将NT值分为2.5-3.4mm、3.5-4.4mm、4.5-5.4mm、5.5-6.4mm、≥6.5mm,其中异常核型比例分别为1/25、0/6、2/4、1/2、5/7,各组的差异具有统计学意义(P<0.05),可以认为不同NT值范围内的染色体异常的检出率不同或不全相同。结论胎儿NT增厚是早孕期筛查胎儿染色体非整倍体异常的有效且敏感的超声指标,绒毛活检行染色体核型分析应作为胎儿NT≥3.5mm的孕妇的首选产前诊断方法。

Objective： To study the significance of chorionic villus karyotype analysis for increased fetal nuchal translucency （NT） at 1 st trimester ultrasound examination. Methods： 120 cases of chorionic villus samplings for karotyping were collected to study the relationship between increased fetal NT and chromosomal karyotypes analysis, then pregnant results were under followed up. Results ： No case with abnormal karyotypes was detected in 76 cases of pregnant women with normal NT （ ≤2. 5 mm）. 9 cases with abnormal karyotypes were detected in 44 cases of pregnant women with abnormal NT （≥2. 5 mm）. The abnormal rate was 20. 45% （9/44）. 1 case with abnormal karyotypes was detected in 25 cases with abnormal NT （2. 5mm≤NT≤3.5 mm） , and the detecting rate was 4% （1/25）. 9 cases with abnormal karyotypes were detected in 19 cases with abnormal NT （NT≥3.5mm）, and the detecting rate was 42. 11% （8/19）. The rate of chromosomal abnormality in the group with NT≥3.5 was significantly higher than that in the group with 2. 5mm ≤ NT≤3.5 mm （ P 〈 0. 05 ）. The range of increased fetal NT were divided into 2. 5 - 3.4mm, 3.5 - 4. 4mm, 4. 5 - 5.4mm, 5.5 -6.4mm, 〉16. 5mm, and tile abnormal rate were 1/25, 0/6, 2/4, 1/2, 5/7 respectively. There were significantly different abnormal rate among these five groups. Conclusion ： Increased NT is one kind of effective and sensitive ultrasound indicator for screening fetal chromosomal aneuploidy at 1 st trimester ultrasound examination. It was the prefered method to perform chorionic villus karyotyping when fetal NT is greater than 3.5 mm.