中文摘要：

目的探讨孕早期超声与孕中期母血清标记物联合筛查评估唐氏综合征（DS）的风险价值。方法回顾性分析2011年至2015年间,在西安交通大学第一附属医院检查和其他医院转诊的具备完整妊娠结局的单胎妊娠孕妇2 730例,所有孕妇均于妊娠11-13^＋6周完成常规超声检查和唐氏综合征相关超声软指标筛查,其中96例孕妇完成了超声胎儿鼻骨探查;2 597例孕妇于妊娠15-19^＋6周完成孕中期DS筛查,检测甲胎蛋白（AFP）,人绒毛膜促性腺激素游离β亚基（Freeβ-h CG）,游离雌三醇（u E3）指标;初步筛查DS风险较高者于妊娠12周至24周,完成无创产前检测（NIPT）。采用羊膜腔穿刺羊水细胞培养与染色体分析确诊的DS病例作为金标准,病例组和对照组按照1：1标准配对,各纳入12例,运用受试者特征曲线（ROC曲线）分析孕早期超声DS筛查软指标、孕中期实验室DS血清学筛查指标、无创产前检测筛查指标在诊断DS中的价值。结果 2 730例孕妇行孕早期超声筛查,其中96例完成胎儿鼻骨超声检查,早期超声显示胎儿鼻骨不显影的筛查阳性率最高,达3.13%;胎儿颈项部透明层厚度（NT）高危的筛查阳性率为1.43%;胎儿颈部水囊瘤和水肿的筛查阳性率均不足1.00%。2 597例孕妇行DS实验室筛查,孕期母体血清检测DS高危和临界高危的阳性率分别为2.04%和3.62%。诊断DS的各类检测筛查方法中,诊断准确性高且具有显著诊断意义的方法为无创产前检测（AUC=0.958,P〈0.05）;诊断准确性中等的方法包括孕早期超声胎儿鼻骨不显影（AUC=0.750,P=0.038）,孕早期超声NT≥3mm（AUC=0.701,P=0.094）和孕中期血清学DS筛查（AUC=0.708,P=0.083）。结论孕早期超软指标、孕中期母血清标志物的应用对胎儿DS具有筛检意义,孕早期胎儿鼻骨不显影的超声软指标对DS筛查有显著意义。应用早期超声和中期血清标志物的联合筛检有助于提高唐氏综?

英文摘要：

Objective To evaluate the value of ultrasound during early pregnancy and maternal serum markers during middle pregnancy for assessing risk of Down＇s syndrome（ DS）. Methods A retrospective analysis was conducted among 2 730 pregnant women with single pregnancy and complete outcomes who took examination in the First Affiliated Hospital of Xi＇an Jiaotong University or transferred from other hospitals from 2011 to 2015. All pregnant women completed routine ultrasonography and DS related ultrasonographic soft indices screening during 11-13^＋6 weeks. Ultrasonic exploration of fetal nasal bone was performed in 96 pregnant women,and second trimester DS screening was performed for 2 597 pregnant women during 15-19^＋6 weeks to detect alpha-fetoprotein（ APF）,free β-h CG and unconjugated estriol（ u E3）. For cases with high risk of DS in primary screening,non-invasive prenatal testing（ NIPT） was done during 12-24 weeks. Amniotic cavity puncture amniotic fluid cell culture and chromosome analysis were taken as gold standard for DS confirmed cases,and twelve patients were included in case group and control group matched by 1： 1. Receiver operator characteristic curve was used to analyze the value of soft indices of ultrasound in early pregnancy,screening indices of DS serology in middle pregnancy,and index of NIPT in diagnosis of DS. Results Among 2 730 pregnant women receiving early ultrasound screening,96 patients completed fetal nasal bone ultrasonography. Early ultrasound showed the highest incidence of no image of fetal nasal bone up to 3. 13%. The screening positive rate of high risk of NT was 1. 43%,and that of fetal neck water cyst and edema was less than 1. 00%. DS laboratory screening was performed among 2 597 pregnant women,and the positive rate of high risk and critical risk of DS detected by maternal serum was 2. 04%and 3. 62%,respectively. In all kinds of screening methods for detection of DS,the method with high diagnostic accuracy and remarkable diagnostic significance was NIPT（ AUC