胎儿颈部透明带厚度检测在产前筛查中的应用

The role of nuchal translucency in prenatal screening.

目的 分析建立中国汉族人群早中孕期各孕周的NT标准值范围；探讨早中孕期进行超声检测胎儿颈部透明带厚度（NT）对筛查胎儿异常在产前诊断中的临床作用。方法自2003年11月始，对在我院产检的所有孕妇从10孕周起进行NT测量，对其中959例在我院结束妊娠、资料完整的病例进行研究，以10—14wNT大于3mm及14w后NT大于5mm为切点（cutoff）值，采用统计学方法进行数据分析，对NT增加者胎儿结局进行分析。结果确立各孕周平均值和95％参考上限。经相关性分析，发现随着孕周的增加，NT有逐渐增加趋势，回归方程：NT=0．0229×孕周一0．1021，（r=0．9692，P〈0．01）：NT与孕妇年龄无明显相关性。以3mm作为风险界定值，其假阳性率为O，以2．5mm设为风险界定值其假阳性率为4．3％，检出率均为100％。共检出5例NT增厚的孕妇，均伴有不良胎儿结局。结论NT检测不仅对于染色体疾病的早期诊断具有重要的意义，而且可以早期发现多种原因造成的胎儿异常，是早中期妊娠阶段产前筛查有效手段之一。应该进行多中心大样本的研究，从而使之制度化和规范化，并获得更为可靠的风险界定值。

Objective： To establish the standard value range of fetal nuchal translucency （NT） in deferent gestational week and to investigate the role of NT measurement in the screening of fetal malformation. Methods ： A total of 959 pregnant women underwent NT screening from November 2003 to April 2005 in Peking University Third Hospital. The cut-off value of risk for trisomy 21 is over 3mm from 10-14 gestational weeks, and 5mm after 14 gestational weeks. Fetal outcomes were evaluated. Results： An elementary referential parameter of the fetal nuchal translucency from 12 to 14 Gestational weeks was obtained. NT was increased with gestational week. The regression equation was NT =0.0229 × （gestation week） -0. 1021, （ r = 0.0229,P 〈0.01）. No difference was found with pregnant age. Taking 3mm as the risk cutoffs, the false negaive rate was zero and with a 100% positive rates; taking 2. 5mm as cut -offs, the false positive rate was 4. 3% with a positive rates of 100%. There were 5 abnormal fetuses with a thick NT. Conclusion： The nuchal translucency measurement by ultrasonograph is a useful method in prenatal screening and diagnosis. There is a relationship not only with chromosome abnormality, but also with other fetal mslformation.