妊娠早期和中期唐氏综合征血清筛查的对比研究

Investigation of Down′s syndrome screening in the early and middle period of pregnancy

目的探讨孕早期和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3255例孕10～13+6周和3518例孕14～20+6周妇女进行血清标记物妊娠相关蛋白A(PAPPA)或甲胎蛋白(AFP)和游离β绒毛膜促性腺激素(freeβHCG)进行检测,筛查结果应用Multicalc软件计算唐氏综合征风险。唐氏综合征风险切割值为1∶250,当其≥1∶250时为唐氏高危孕妇,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6773例孕妇,唐氏综合征筛查阳性孕妇352例,假阳性率为5.2%(349/6773)。有218例接受了脐血穿刺产前诊断,占总筛查高危孕妇的52.5%(218/415)。发现胎儿染色体异常34例,异常检出率为15.6%(34/218),其中3例唐氏综合征,1例18三体,1例XXX体在孕中期筛查中发现,1例唐氏综合征儿在孕早期筛查中漏诊。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31.1%和11.6%,差异有显著性(P<0.05)。结论血清标记物AFP+freeβHCG筛查三体综合征较PAPPA+freeβHCG好,唐氏综合征血清筛查是预测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价值。

Objective To explore the practical value of Down＇s syndrome screening in the early and middle period of pregnancy in detecting chromosomal disease and the poor outcome of pregnancy. Methods Serum PAPP-A or AFP and free-β-HCG levels of 3255 pregnant women with 10-13^＋6 weeks and serum AFP and of 3518 pregnant women with 14-20^＋6 weeks were detected by time-distinguished fluorescence immunoassay. Down＇s syndrome risk value was calculated with Multiealc software, with cut-off value of 1： 250. The pregnant women whose value was ≥ 1：250 would be at high risk of Down＇s syndrome and needed to have the cordocentesis for fetal karyotype after 20 weeks of pregnancy. Results 6 773 pregnant women accepted antenatal screening,352 of which were detected positive for Down＇s syndrome with false positive rate of 5.2% （349/6773）. 218 cases received fetal karyotypes, accounting for 52.5% （218/415）, detecting fetal abnormal chromosome in 34 cases with detecting rate of 15.6% （34/ 218） ,including three cases of Down＇s syndrome （one case of 18-trisome and one ease of X-trisome by the serum screening in the middle period, while another one was misdiagnosed in the early screening ）. The poor outcome of pregnancy was 31.1% and 11.6% in high-risk group and low risk group of Down＇s syndrome,with significant difference （P 〈 0.05 ）. Conclusion The serum AFP and free-β-HCG levels of pregnant women are more effective in screening trisome fetus than PAPP-A ＋ free-β-HCG. The serum screening of Down＇s syndrome would be a practical method of preventing the congenital defect of fetus.