分析我院无创基因检测对胎儿常见染色体非整倍体异常的检测效果，探讨不同检测孕周、孕妇年龄与检测效果指标的相关性。

选择自2013年6月至2019年4月在北京大学深圳医院行无创产前基因检测(non-invasive prenatal DNA testing, NIPT)的孕妇，对检测结果高风险者进行羊水染色体核型分析，对检测低风险者行电话随访，以核型分析和随访结果判断胎儿是否异常，分析NIPT的检测效果指标。按孕妇年龄分为<30岁、30~34岁、35~39岁和≥40岁4个各组，按检测孕周分为≤13⁺⁶、14~22⁺⁶周、23~27⁺⁶周和≥28周4个组，探讨灵敏度、特异度、阳性预测值、假阳性率等指标与孕妇年龄及检测孕周的相关性。

(1)共43 918例行NIPT孕妇纳入统计，NIPT总体的灵敏度100.00%，特异度99.76%，假阳性率0.24%；(2)NIPT对第21、18、13及性染色体异常的灵敏度、特异度均在99%以上，假阳性率低于0.5%；(3)年龄分组中35~39岁组与30~34岁组的特异度(99.67% vs 99.81%)相比，差异有统计学意义( χ²＝4.099，P＝0.043)，其余筛查指标差异均没有统计学意义。孕周分组数据筛选指标比较，差异均没有统计学意义(P>0.05)；(4)假阳性病例中发现2例新生儿患有先天性心脏病，1例新生儿双肾盂轻度分离，1例多发畸形等非染色体畸形异常。

NIPT对常见染色体非整倍体异常具有较高的准确性及特异性，较低的假阳性率，特别是21-三体。NIPT对于不同年龄、不同孕周的孕妇检测效果差异不大。对于NIPT结果阳性病例，需警惕胎儿非染色体畸形等异常的发生。

To analyze the detection effect of non-invasive prenatal testing (NIPT) on detecting fetal common chromosome aneuploidy abnormalities in Peking University Shenzhen Hospital, and to explore the correlation between different gestational weeks, maternal age and detection effect indicators.

Pregnant women who underwent NIPT and were with high risk result in Peking University Shenzhen Hospital from June 2013 to April 2019, were selected to analyze amniotic fluid chromosome karyotype, and others with low risk were followed-up by telephone. Basing on the chromosome karyotype results and follow-up results, the fetus was diagnosed and analyzed the NIPT detection effect index. According to the maternal age, they were divided into 4 groups: < 30 years old group, 30~34 years old group, 35~39 years old group, ≥ 40 years old group. According to the gestational age, they were divided into 4 groups: ≤13^{+ 6} weeks group, 14-22^{+ 6} weeks group, 23-27^{+ 6} weeks group, ≥ 28 weeks group. The correlation of sensitivity, specificity, positive predictive value and false positive rate with maternal age and gestational age were analyzed.

(1) A total of 43, 918 pregnant women with NIPT were included in the statistics. The overall sensitivity of NIPT was 100.00%, the specificity was 99.76% and the false positive rate was 0.24%.(2) The sensitivity and specificity of NIPT to T21, T18, T13, and sex chromosome abnormalities were all over 99% and the false positive rate was less than 0.5%. (3) In the advanced age group, there was a statistically significant difference in the specificity between the 35~39-year-old group and the 30~34-year-old group (P<0.05), and the differences in other screening indicators were not statistically significant. There was no statistically significant difference in the screening index comparison of grouped data during gestational week (P<0.05). (4) Among the false positive cases, it was found that 2 cases of newborns had congenital heart disease, 1 case with slight separation of double renal pelvis and 1 case with multiple abnormalities and other non-chromosomal abnormalities.

Non-invasive prenatal testing (NIPT) had high accuracy and specificity for common chromosome aneuploidy abnormalities, and low false positive rate, especially for trisomy 21. There is no significant difference in the detection effect of NIPT for pregnant women in different ages and different gestational weeks. For the cases with positive NIPT results, it was necessary to guard against the occurrence of fetal non-chromosome abnormalities and other abnormalities.