Retrospective study on NIPT or NIPT plus combined with ultrasound in screening fetal chromosomal abnormalities

This retrospective study analyzed 306 pregnant women, with 182 undergoing genetic testing using NIPT plus and CMA, and 124 undergoing standard NIPT and CMA. The study aimed to compare the clinical performance of NIPT and NIPT plus in prenatal evaluation by using CMA as the gold standard to assess the diagnostic efficiency of the two screening methods. NIPT plus and NIPT results were correlated with ultrasound findings to evaluate their accuracy and clinical utility. The diagnostic performance of each method was compared against CMA to assess sensitivity, specificity, false positive and false negative rates, as well as positive predictive value and negative predictive value. The combined use of NIPT plus and ultrasound significantly improved the detection rate of sex chromosome aneuploidy (SCA), microdeletion/microduplication syndromes (MMS), and rare autosomal trisomies (RAT) compared to NIPT plus alone. Ultrasound combined with NIPT plus achieved the highest sensitivity (88.24%) for SCA/RAT/ MMS. However, NIPT plus exhibited a higher false positive rate compared to standard NIPT. In contrast, NIPT combined with ultrasound demonstrated the highest PPV (88.89%) for common trisomies (T13, T18, T21). False negatives were more prevalent in standard NIPT, particularly for SCA, MMS, and RAT, emphasizing its limitations for detecting complex chromosomal abnormalities. NIPT plus, when combined with ultrasound, offers significant improvements in the detection of rare chromosomal abnormalities like SCA, MMS, and RAT, while maintaining high detection rates for common trisomies. Although NIPT plus has a higher false positive rate, the inclusion of ultrasound enhances screening accuracy and clinical decision-making. This study supports the use of NIPT plus combined with ultrasound as the optimal screening strategy, particularly for rare and complex chromosomal abnormalities, while standard NIPT remains highly effective for screening common trisomies.