探讨孕中期唐氏综合征(DS)等筛查对检出胎儿出生缺陷和不良妊娠结局的实用价值。

选择2006年12月至2008年12月在本院接受孕中期(妊龄为14～20孕周)二联生化指标筛查及分娩的3275例孕妇为研究对象。孕中期二联生化指标为血清甲胎蛋白(AFP)和游离β－绒毛膜促性腺激素(fβ－hCG)检测，并结合孕妇年龄、体重指数(BMI)、孕周、胎数、糖尿病史及吸烟史等因素，采用DS等风险专用分析软件Risks2T分析DS，18－三体综合征及神经管缺陷(NTD)发生风险率。对二联生化指标筛查结果呈阳性者再行彩色多普勒超声、羊水或脐带血穿刺产前诊断进行确诊(本研究遵循的程序符合本院人体试验委员会所制定的伦理学标准，得到该委员会批准，并与受试对象签署临床研究知情同意书)。

本组孕中期二联生化指标对胎儿缺陷的检出总阳性率为9.22%(302/3275)，真阳性率为1.74%(57/3275)，假阴性率为0.49%(16/3275)，而检出率为78.1%(57/73)。本组DS筛查阳性率为7.80%(261/3275)，真阳性率为0.18%(6/3275)，假阴性率为0.09%(3/3275)；18－三体综合征筛查阳性率为0.73%(24/3275)，真阳性率为0.12%(4/3275)，假阴性率为0%(0/3275)；NTD筛查阳性率0.52%(17/3275)，真阳性率为0.15%(5/3275)，假阴性率0.06%(2/3275)。本组胎儿其他染色体异常为2例，二联生化指标均呈阳性。胎儿其他畸形为53例，其中42例经二联生化指标筛查检出。

孕中期二联生化指标筛查胎儿DS等是行之有效的，不仅可发现预期筛查疾病，也可发现其他胎儿发育异常。二联生化指标进行产前筛查，结合彩色多普勒超声是提高胎儿出生缺陷检出率的有效手段。

To explore the practical value of Down's screening in the middle period pregnancy in detecting congenital birth defect and predicting the outcome of pregnancy.

Select 3275 cases of pregnant women who received the second trimester (gestation of 14 to 20 weeks of gestation) were inspected by the maternal serum screening during December 2006 to December 2008. Alpha fetoprotein AFP and Free β-hCG in mother's blood serum were inspected by automatic chemical radiation method, meanwhile, combining the age, body mass index, gestational age and whether or not twins, diabetes mellitus history, smoking history to count the risk probability of Down's syndrome, Edwards' syndrome and neural tube defects by using the DS-specific risk analysis software were the maternal serum screening. The pregnant women whose value at high risk were diagnosed by the ultrasonography, amniotic fluid or cord blood paracentesis(In this study, the procedures followed to comply with the ethical standards developed by the hospital IRB, were approved by the Committee, and the clinical research informed consent were signed by the subjects.).

The fetal defects' screening total positive rate of the serum markers during the second trimester in this group was 9.22%(302/3275), the true positive rate was 1.74%(57/3275), the false negative rate was 0.49%(16/3275), the detection rate was 78.1%(57/73). The positive rate of the Down's screening in this group was 7.80%(261/3275), the true positive rate was 0.15%(6/3275), the false negative rate was 0.09%(3/3275). The positive rate of the Edwards' syndrome screening was 0.73%(24/3275), the true positive rate was 0.12%(4/3275), the false negative rate was 0%. The positive rate of the neural tube defects screening was 0.52%(17/3275), the true positive rate was 0.15%(5/3275), the false negative rate was 0.06%(2/3275). Two cases of chromosome abnormality were both positive on screening of the serum markers in this group. A total of 53 cases were other various kinds of malformation, among them, 42 cases were positive on maternal serum screening.

Two associated biochemical maternal serum screening of pregnant women during second-trimester were effective indexes to screen abnormal fetus and predict outcome of pregnancy and fetus, combined with ultrasonography, which would be a practical method of preventing congenital defect.