绒毛膜性质对双胎早期唐氏征筛查的影响

The effection of choriontity on twin′s first-trimester prenatal screening

目的通过比较不同绒毛膜性对双胎早期唐氏筛查风险的影响,指导双胎早期唐氏筛查的风险计算。方法收集2014年7月至12月于湖南省妇幼保健院行唐氏筛查的170例自然妊娠双绒毛膜双羊膜囊双胎孕妇,用双绒毛膜双羊膜囊、单绒毛膜双羊膜囊及单绒毛膜单羊膜囊分别计算风险并追踪妊娠结局,比较用不同绒毛膜性进行风险计算所造成的差异。结果按双绒毛膜双羊膜囊、单绒毛膜双羊膜囊及单绒毛膜单羊膜囊计算的妊娠相关蛋白A中位数倍数(PAPP-A MOM)分别为2.19,1.20,1.37;人绒毛膜促性腺激素游离β亚基中位数倍数(free HCGβMOM)分别为2.02,1.09,1.36。按双绒毛膜双羊膜囊、单绒毛膜双羊膜囊及单绒毛膜单羊膜囊计算所得唐氏综合征高风险例数分别为13例、10例和7例,假阳性率分别为7.65%,5.88%,4.12%。追踪所有孕妇妊娠结局,其中双胎之一发生染色体异常者2例,双胎之一停育者2例,双胎停育者1例,1例双胎之一为心脏室间隔缺损,出生后行手术修补,1例双胎出生后均确诊为先天性甲状腺功能减低症。结论运用不同绒毛膜性进行双胎早期唐氏筛查风险计算,血清生化指标及风险值会发生显著变化,应按照孕妇真实情况详细描述双胎绒毛膜性,避免错误风险计算及漏筛情况的发生。

Objective：To study whether there were significant difference among different choriontity for guiding the clinical twin′s first-trimester prenatal screening. Method：Collecting 170 cases of natural twin pregnancy samples from July 2014 to December 2014. All cases were dichorionic diamniotic（DCDA）. Using different choriontity such as dichorionic diamniotic,monochorionic diamniotic（MCDA）,monochorionic monoamniotic（MCMA）calculated the risk of Down′s syndrome at the first-trimester pregnancy. The difference were analyzed combined with the pregnancy results were followed up. Results：According to different choriontity（DCDA,MCDA,MCMA）,the multiple of median PAPP-A were 2.19,1.20,1.37. The multiple of media free HCG β were 2.02,1.09,1.36. The high risk cases number of Down′s syndrome were 13,10,7. The false positive rate of Down′s syndrome were 7.65%,5.88%,4.12%. The pregnancy results found 6 abnormal cases. Chromosome abnormality occurred in two cases. Single intrauterine fetal death（s IUFD）happened in two cases. One case miscarry at 13 weeks. Two babies were diagnosed as Congenital hypothyroidism in one case. Conclusion：Using different choriontity calculate the first-trimester Down′s syndrome risk,the multiple media of serum marker were significant difference. The risk values were also significant different. Hence,we should describe the choriontity of twin pregnancy,calculate the Down′s syndrome risk correctly to avoid the mistakes.