摘要目的:分析747例孕妇外周血胎儿游离DNA产前筛查高风险胎儿产前诊断结果及妊娠结局。方法:选取2015年1月至2022年3月在南京鼓楼医院因孕妇外周血胎儿游离DNA无创产前筛查(NIPT)高风险行羊膜腔穿刺产前诊断的747例病例，均行羊水细胞染色体核型分析和/或染色体微阵列分析。对所有病例进行查阅分娩资料或电话等形式的随访并记录结果。组间采用 χ2检验或者 F检验进行统计学处理。 结果:747例NIPT高风险孕妇中387例为真阳性，整体阳性预测值(PPV)为51.81%。NIPT对21三体(T21)、18三体(T18)、13三体(T13)、性染色体非整倍体(SCA)高风险的PPV分别为80.24%(199/248)、60%(48/80)、14%(7/50)、38.97%(106/272)，对T21的PPV显著高于T18和T13( P<0.001)。NIPT对其他染色体非整倍体高风险和染色体拷贝数变异(CNV)的PPV分别为11.11%(5/45)和40.74%(22/52)。对X染色体增加的PPV明显高于X染色体减少(64.29% vs. 22.22%， P<0.05)。高龄(≥35岁)孕妇总体PPV显著高于低龄组(69.35% vs. 42.39%， P<0.001)。T21、T18的 Z≥10组PPV明显高于3≤ Z<5组和5≤ Z<10组( P<0.05)。52例CNV高风险中，≤5 Mb的PPV显著高于5 Mb<CNV≤10 Mb和>10 Mb(60% vs. 30%；60% vs. 23.53%， P<0.05)。387例真阳性病例中，322例引产，53例分娩且生长发育未见异常，12例失访。 结论:NIPT对常见非整倍体异常的PPV与孕妇年龄及 Z值相关，高龄人群、高 Z值组的阳性预测值较高。

abstractsObjective:To analyze the results of prenatal diagnosis and outcome of pregnancy for women with a high risk for fetal aneuploidies.Methods:A total of 747 cases of prenatal diagnosis by amniocentesis due to high risks by non-invasive prenatal testing (NIPT) were selected from January 2015 to March 2022 in the Drum Tower Hospital Affiliated to Nanjing University Medical School. The amniotic fluid samples were subjected to chromosomal karyotyping and/or chromosomal microarray analysis. All cases were followed up by searching the birth information or telephone calls, and the results were recorded. 2 test or F test were used for comparing the difference between the groups.Results:Among the 747 pregnant women with a high risk by NIPT, 387 were true positives, and the overall positive predictive value (PPV) was 51.81%. The PPVs for trisomy 21 (T21), trisomy 18 (T18), trisomy 13 (T13) and sex chromosome aneuploidies (SCA) were 80.24% (199/248), 60% (48/80), 14% (7/50) and 38.97% (106/272), respectively. The PPV for T21 was significantly higher than T18 and T13 ( χ2= 85.216, P<0.0001). The PPV for other chromosomal aneuploidies and copy number variations (CNVs) were 11.11% (5/45) and 40.74% (22/52), respectively. The PPV for increased X chromosomes was significantly higher than X chromosome decreases (64.29% vs. 22.22%, χ2= 5.530, P<0.05). The overall PPV for elder women (≥ 35 years old) was significantly higher than younger women (69.35% vs. 42.39%, χ2= 49.440, P<0.0001). For T21 and T18, the PPV of Z ≥ 10 group was significantly higher than that for 3 ≤ Z < 5 group or 5 ≤ Z < 10 group ( P<0.05). Among 52 cases with a high risk for CNVs, the PPV for the ≤ 5 Mb group was significantly higher than the 5 Mb < CNVs < 10 Mb or > 10 Mb groups (60% vs. 30%和60% vs. 23.53%, P<0.05). Among the 387 true positive cases, 322 had opted for induced labor, 53 had delivered with no abnormal growth and development, and 12 were lost during the follow-up. Conclusion:The PPVs for common chromosomal aneuploidies are related to the age and Z value of the pregnant women, which were higher in the elder group and higher Z value group. In addition, the PPV is associated with high risk types. The PPV for T21 was higher than T18 and T13, and that for 45, X was lower than 47, XXX, 47, XYY or 47, XXY syndrome. NIPT therefore has relatively high PPVs for the identification of chromosomal CNVs.