目的 探讨妊娠11~14周，胎儿颈项透明层厚度（NT）≥3mm时与其染色体异常的相关性。方法 对73例胎儿颈项透明层厚度≥3mm的孕妇行早期胎儿绒毛或中期羊水穿刺取样，经细胞培养后制备成染色体进行核型分析。结果 73例样本中，10例早期超声NT增厚，错过绒毛取材的最佳时间，给予羊水穿刺取样；63例经绒毛活体取材，培养均获得成功，并发出染色体核型分析报告，成功率为100%。73例NT值增厚的病例中，染色体核型异常10例，异常比例是13.70%。其中3例羊水染色体异常，7例绒毛染色体异常。异常核型中：22三体1例；21三体2例、18三体2例、16三体1例、13三体1例，45,XO 1例，47,XXY1例，染色体多态性变异1例。结论 胎儿颈项透明层增厚与染色体异常相关性大，胎儿染色体的异常可导致其颈项透明层厚度增加。实验证明，胎儿颈项透明层的厚度测量是产前遗传学检查的重要指征之一。对妊娠期妇女超声筛查胎儿NT值≥3mm的孕妇，应建议其行胎儿染色体的核型分析，及时明确诊断，避免异常儿的出生。
Objective To investigate the performance of fetal nuchal translucency thickness(NT) in pregnancies whose gestation were11~14week,and study the association between NT≥3mm and chromosomal abnormalitiesin Fetus. Method An NT measurement was made in 73 fetuses through sonographic screening, we advised pregnancies with NT≥3mm to undergo chorionic villus sampling and amniocentesis, and then analyzed chromosomal karyotype. Results In a total of 73 cases, there were 10 samples of early stage decreased NT missing right time of chorionic villus sampling which we used by amniocentesis, and 63 samples of fetal villus. the cultivated successful rate was 100%. We identified 10 chromosomal abnomal karyotypes among the 73 fetuses, the dectection rate was 13.70%. There were 3 cases of amniotic fluid chromosomal abnormalities and 7 cases of fetal villus chromosomal abnormalities. Of these, including 1 fetuse with trisomy 22, 1 fetuse with trisomy 21, 2 fetuses with trisomy 18, 1 fetuse with trisomy 16, 1 fetuse with trisomy 13, 1 fetuse with 45,XO,1 fetuse with 47,XXY,1 fetuses with chromosomal polymorphism abnormalties. Conclusions Increased fetal NT thickness was associated with a high incidence of chromosomal abnormalities. Fetal chromosomal abnormalitie might lead to fetal NT thickness increased. NT measurement is one of important screenings in antenatal genetics examization.when NT≥3mm through sonographic screening, fetal chromosomal analyze is necessary to avoid the birth of abnormal babies.
