Patient characteristics and clinical indication.

BackgroundCell-free DNA (cf-DNA) screening for common trisomies has been increasingly assimilated into prenatal care. In this study, we evaluated the Z-score accuracy and the effectiveness of non-invasive prenatal testing (NIPT) for trisomies 21, 18, and 13 using cf-DNA, and further analyze pregnancy outcomes of NIPT-positive pregnant women.MethodsThis retrospective study analyzed pregnancies that yielded positive NIPT results at Shaoxing Maternity and Child Health Care Hospital between 01/01/2017 and 31/12/2022. Invasive prenatal diagnosis (IPD) confirmed the positive NIPT findings. Logistic regression analysis was applied to correlation analysis of Z-scores and positive predictive value (PPV). Accuracy of Z-score was evaluated through receiver operating characteristic (ROC) curve analysis. Data regarding basic characteristics, prenatal diagnosis results, and pregnancy outcomes were collected.ResultsIn total,257 high-risk cases of trisomy 21, 18, and 13 were identified. Among these,193 pregnancies underwent invasive prenatal diagnosis (IPD) in our institution, the PPV was 75.44% for T21,45.28% for T18, and 17.86% for T13. A significant association between Z-scores and PPVs were revealed by logistic regression(p ConclusionsThe study demonstrates that the Z-score is valuable in accurately assessing NIPT results. Consequently, clinicians can provide more efficient prenatal genetic counseling by utilizing a specific reference value for the Z-score.