孕早期唐氏综合征的血清筛查和产前诊断研究

Serological screening and antenatal diagnosis of patients with Down's syndrome in early pregnancy

目的 探讨孕早期唐氏综合征筛查的实用价值。方法应用时间分辨荧光免疫法对4186例孕早期（10～13^＋6周）妇女进行血清标记物（PAPP-A＋free-β-hCG）二项指标双标试剂盒检测，筛查结果应用Muhieale软件计算唐氏综合征风险。唐氏综合征风险切割值为1：250，当≥1：250时为唐氏综合征高危孕妇。于孕18周以后抽胎儿的脐血进行胎儿核型分析。结果产前筛查4186例孕妇，筛查唐氏综合征高危孕妇233例，假阳性率为5．5％，有138例接受了羊水或脐血产前诊断，发现3例唐氏综合征，其中1例唐氏综合征儿是漏诊，其它胎儿染色体异常共21例，异常检出率为15．2％。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26.1％和10．5％，差异有显著性（P〈0．05）。结论孕早期血清PAPP-A和free-β-hCG标记物是产前筛查异常胎儿的有效指标，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 syndrome screening in early pregnancy. Methods Serum （PAPP-A and free-β-hCG） level of 4 186 pregnant women （at 10 - 13^ ＋6 weeks of congestation） were detected by time-distinguished fluorescence immunoassay. Downg syndrome risk value was calculated with Muhicalc software, its cut-off value was 1：250. The pregnant women whose risk value was higher than or equal to 1 ： 250 were regarded as to be at high risk and need to receive cordocentesis for fetal karyotype analysis after 18 weeks of congestation. Results 4 186 pregnant women underwent antenatal screening, 233 of them were in high risk of Down＇s syndrome, and the false positive rate was 5.5%. Fetal karyotypes of 138 cases were examined by cordocentesis, Three cases of Down＇s syndrome （one of them was leaked by diagnosis ） and 21 cases with fetal other abnormal chromosome were determined. The detectable rate was 15.2%. There was significant difference in rate of abnormal outcome of pregnant women and fetuses in the two groups （ high risk and low risk of Down＇ s syndrome groups） （26.1% and 10.5 % respectively, P 〈 0.05 ）. Conclusion Serum PAPP-A and free- β-hCG level of pregnant women in the first-trimester were effective index to identify those abnormal fetuses. As combined with antenatal diagnosis, it would be a practical method of preventing congenital defects.