胎儿孕周对中期唐氏筛查效率的影响

Effects of fetus gestational weeks on efficiency of Down's Screening during the second trimester

目的观察分析胎儿妊娠中期对唐氏综合征筛查效率的影响,为临床提供一定的参考数据。方法选取中期产前筛查的孕妇共36515例。根据孕周进行分组,共分为5组,分别为15孕周组(15~15+6)、16孕周组(16~16+6)、17孕周组(17~17+6),18孕周组(18~18+6)、19孕周组(19~20周)。对比不同孕周孕妇唐氏综合征患儿检出率和筛查假阳性率。结果孕周在15周组的孕妇有出现2例漏诊的病例,其中孕周在16周到18周的唐氏筛查检出率为100%。孕周在19周组孕妇没有确诊唐氏综合征患儿,因此假阳性率是7.85%。不同孕周段的筛查结果不同,其中孕周在16~18周的检出率为100%,筛查的假阳性率为4.36%。筛查阴性组孕妇AFP值随着孕周增加而增加,HCG值随着孕周增加而减少。筛查阳性组孕妇AFP均低于筛查阴性组,而HCG值则是比阴性组要高。结论唐氏综合征筛选在孕周期中期的16~18周进行检查,其筛查效果最高。

Objective To observe and analyze the effects of fetus gestational weeks on efficiency of Down’s screening during the second trimester, and to provide certain reference data clinically. Methods A total of 36515 puerpera who received prenatal screening during the second trimester were selected. They were assigned to 5 groups according to their gestational weeks, which were group of 15 gestational weeks(15 to 16+6), group of 16 gestational weeks(16 to16+6), group of 17 gestational weeks(17 to 17+6), group of 18 gestational weeks(18 to 18+6) and group of 19 gestational weeks(19 to 20 weeks). Detection rate and false screening positive rate of infants with Down’s syndrome were compared between different gestation weeks. Results Two cases of missed diagnosis were seen in puerpera in the group of 15 gestation weeks. Detection rate of Down’s screening in the group of 16 weeks to 18 weeks was 100%.No diagnosed infants with Down’s syndrome were seen in the group of 19 gestational weeks. The false positive rate therefore was 7.85%. The screening results were different during different gestational weeks. Detection rate during 16 to18 gestation weeks was 100%, and false positive rate of screening was 4.36%. In the negative groups of screened puerpera, AFP level increased with the increase of gestational weeks, and HCG level decreased with the increase of gestational weeks. In the positive groups of screened puerpera, their AFP levels were all lower than those in the negative groups, and there HCG levels were higher than those in the negative groups. Conclusion Efficiency of screening is high when Down’s screening during the second trimester of pregnancy is carried out during 16 to 18 gestational weeks.