ObjectiveTo analyze the antenatal diagnosis and pregnancy outcome in high risk pregnant women with positive results of the non-invasive prenatal DNA testing, and discuss its clinical significance.

MethodsThe non-invasive prenatal DNA testing in 5 077 pregnant women were implemented, the free fetal DNA in maternal peripheral blood of the second generation was sequenced.The positive was confirmed by the cell karyotype detected by amniocentesis, and followed up by telephone.

ResultsAmong 5 077 pregnant women detected by non-invasive prenatal DNA testing, the high risk in 64 cases was identified, which included 28 cases of 21-trisomy, 4 cases of 18-trisomy, 3 cases of 13-trisomy, 14 cases of sexual chromosome abnormality, 8 cases of other chromosome abnormality and 7 cases of microdeletion and microduplication.Amniocentesis was performed in 54 cases, the results showed that 23 cases were confirmed among 24 cases of 21-trisomy, 2 cases were confirmed among 4 cases of 18-trisomy, 1 case was confirmed among 3 cases of trisomy, 5 cases were confirmed among 11 cases of sex chromosome, no case was confirmed among 6 cases of other chromosomes, and 2 cases were confirmed among 6 cases of micro deletion and micro duplication.The non-invasive DNA testing results showed 1 case was negative, the ultrasound examination suggested the multiple abnormalities, and the amniocentesis result showed which was the 18-trisomy.

ConclusionsThe positive predictive value of 21-trisomy syndrome is higher by the non-invasive prenatal DNA testing, but the false positive and false negative result still occur, which cannot completely replace karyotype analysis.The non-invasive DNA prenatal testing is still far from the positive predictive value of 18-trisomy syndrome and 13-trisomy syndrome, but it can detect micro-deletion and micro-repetition abnormalities, which has irreplaceable superiority over the karyotype analysis.