3195例孕中期唐氏综合征的血清筛查和产前诊断临床分析

Analysis of down's syndrome screening and antenatal diagnosis of 3195 cases in the middle period of pregnancy

目的探讨孕中期唐氏综合征筛查对检出胎儿染色体异常和妊娠不良结局的实用价值。方法应用时间分辨荧光免疫法对3195例孕中期(14～20+6周)妇女进行血清标记物(AFP+free-β-HCG)二项指标双标试剂盒检测,筛查结果应用Multicalc软件计算唐氏综合征风险。唐氏综合征(down'ssyndrome,DS)风险切割值为1∶250,当≥1∶250时为DS高危孕妇,于孕20周以后抽胎儿的脐血进行胎儿核型分析,追踪胎儿和孕妇的情况。结果产前筛查3195例孕妇,筛查高危孕妇232例,阳性率为7.3%,其中唐氏综合征筛查阳性孕妇169例,假阳性率为5.2%。有147例接受脐血穿刺产前诊断,占筛查DS高危孕妇的63.3%。发现胎儿染色体异常19例,异常检出率为12.9%。其中3例唐氏综合征,1例18-三体,1例XXX体。唐氏筛查高风险度组和低风险度组的妊娠不良结局分别为30.2%和12.3%,差异有显著性(P<0.05)。结论孕中期产前筛查是预测异常胎儿和不良妊娠结局的有效指标,再结合产前诊断对防止先天缺陷有实用性价值。

[Objective] To explore the practical value of Down＇ s screening in the middle period pregnancy in detecting chromosomal disease and congenital birth defect and predicting the outcome of pregnancy. [Methods] Serum AFP and free-β-HCG level of pregnant women（14-20^＋6 weeks） were detected by time-distingnished fluorescence immunoassay, Down＇ s syndrome risk value was calculated with Multicalc software, its cut-off value was 1： 250. The pregnant women whose value are higher than or equal to 1：250 would be at high risk and need to have the cordocentesis for fetal karyotype after 18 weeks. [Results] 3195 pregnant women accepted antenatal screening, 232 cases of them were detected at high risk, and positive rate was 7.3%,including 169 cases of high risk with Down＇ s syndrome（fasle positive rate 5.2%）. Fetal karyotypes of 147 cases diagnosed by the cordocentesis, 19 cases with fetal abnormal chromosome, the detectable rate was 12.9%,including three cases of Down＇ s syndrome, a case of 18-trisome and a case of X-trisome. There is signification different in the rate of the abnormal outcome of pregnant women and fetuses in two groups of high risk and low risk of Down＇ s syndrome （30.2% and 12.3% respectively, P 〈0.05）, [Conclusion] The serum AFP and free-β-HCG level of pregnant women during second-trimester were effective indexes to screen abnormal fetus and predict outcome of pregnancy and fetus, which would be a practical method of preventing congenital defect.