了解内蒙古自治区无创产前基因检测(NIPT)结果为高危孕妇的染色体异常状况，以及该自治区开展NIPT技术情况。

选取2013年3月至2017年7月，因NIPT结果提示为高危，而于内蒙古医科大学附属医院进行羊膜腔穿刺术产前诊断的82例孕妇为研究对象。根据其接受NIPT前是否存在羊膜腔穿刺术产前诊断指征，将其分为有指征组(n＝68)和无指征组(n＝14)。采用回顾性分析方法，采集这82例孕妇的临床病例资料，对其来源地区、接受NIPT前是否存在羊膜腔穿刺术产前诊断指征，以及NIPT与羊膜腔穿刺术诊断胎儿染色体异常的结果，进行统计学分析。采用χ²检验，对2组孕妇的胎儿染色体异常检出率进行比较。本研究遵循的程序符合内蒙古医科大学附属医院人体试验委员会所制定的伦理学标准，经过该伦理委员会批准，进行羊膜腔穿刺术前与所有孕妇签署知情同意书。2组孕妇的年龄、孕龄等一般临床资料比较，差异均无统计学意义(P>0.05)。

①本研究82例NIPT高危孕妇的地区分布前3位为：58.5%(48/82)来自呼和浩特市，11.0%(9/82)来自鄂尔多斯市，8.5%(7/82)来自包头市。②这82例NIPT高危孕妇在接受NIPT前，82.9%(68/82)有羊膜腔穿刺术产前诊断指征，具体包括：高龄(≥35岁)妊娠(36.6%，30/82)，母体血清学筛查结果为高危(30.5%，25/82)，胎儿产前超声检查结果异常(15.8%，13/82)；17.1%(14/82)无羊膜腔穿刺术产前诊断指征。③这82例NIPT高危孕妇中，经羊膜腔穿刺术共计检出胎儿染色体异常为52例，胎儿染色体异常检出率为63.4%(52/82)。NIPT对于胎儿常染色体异常(21-、18-、13-三体)检出率为85.7%(36/42)，对于胎儿性染色体异常检出率为45.7%(16/35)。④有指征组NIPT高危孕妇的胎儿染色体异常检出率为73.5%(50/68)，显著高于无指征组NIPT高危孕妇的14.3%(2/14)，二者比较，差异有统计学意义(χ²＝17.563，P<0.001)。

NIPT技术的应用，有助于改善内蒙古自治区产前非整倍体筛查力量不足状况，但是在开展NIPT筛查的指征确定方面，临床迄今尚缺乏统一认识，而且本院的采取NIPT筛查染色体异常的假阳性率明显高于其他地区。使用目前临床常用的产前筛查手段对孕妇进行产前初步筛查，可有效提高NIPT筛查的阳性率。

To grasp the situation of chromosome abnormalities of pregnant women with high-risk in noninvasive prenatal testing (NIPT) in Inner Mongolia Autonomous Region and the application of NIPT in this region.

From March 2013 to July 2017, a total of 82 pregnant women with high-risk in NIPT and then received amniocentesis in the Affiliate Hospital of Inner Mongolia Medical University were collected as research subjects. They were divided into indication group (n=68) and non-indication group (n=14) according to whether they were combined with prenatal diagnosis indications of amniocentesis or not before receiving NIPT. Retrospective analysis was conducted to collect clinical data of these 82 pregnant women, including origin areas of pregnant women, prenatal diagnosis indications of amniocentesis before receiving NIPT, fetal chromosomes abnormalities diagnosed by NIPT and amniocentesis, and statistical analysis was performed. Chi-square test was used to compare the detection rates of fetal chromosome abnormalities between two groups. The study protocol was approved by the Ethical Review Board of Investigation in Human Being of Affiliate Hospital of Inner Mongolia Medical University. Informed consent was obtained from each participant before amniocentesis. There were no statistical differences between two groups in the aspects of age, gestational age, and so on (P>0.05).

①Among 82 pregnant women with high-risk in NIPT in this study, 78.0% (64/82) of them were from three major cities in the Inner Mongolia Autonomous Region which were Hohhot (58.5%, 48/82), Ordos (11.0%, 9/82), and Baotou City (8.5%, 7/82). ②Among those 82 pregnant women with high-risk in NIPT in this study, 82.9% (68/82) pregnant women were combined with prenatal diagnosis indications of amniocentesis before receiving NIPT, including advanced age (≥35 years old) (36.6%, 30/82), high risk in maternal serum screening (30.5%, 25/82), abnormal results of prenatal ultrasonography (15.8%, 13/82); and 17.1% (14/82) of them were not combined with prenatal diagnosis indications of amniocentesis before receiving NIPT. ③Among those 82 pregnant women with high-risk in NIPT in this study, a total of 52 cases of fetal chromosomes abnormalities were detected by amniocentesis, and the detection rate of fetal chromosome abnormalities was 63.4% (52/82). The detection rate of NIPT for fetal autosomes abnormalities (21-, 18-, and 13-trisomy) was 85.7% (36/42), and the detection rate of NIPT for fetal sex chromosome abnormalities was 45.7% (16/35). ④The detection rate of fetal chromosome abnormalities in indication group was 73.5% (50/68), which was significantly higher than that in non-indication group 14.3% (2/14), and the difference was statistically significant (χ²=17.563, P<0.001).

The application of NIPT technology in Inner Mongolia Autonomous Region has improved the deficiency of prenatal aneuploid screening in this region. However, there is still a lack of consensus in clinical practice so far in the indications of NIPT screening. And the false positive rate of NIPT screening for chromosomal abnormalities in our hospital is significantly higher than that in other regions. In addition, using the prenatal screening methods common in current clinical trials for initial prenatal screening could effectively improve the positive detection rate of NIPT.