Results and indications changes by prenatal diagnosis of 3,458 pregnant women: a 10-year retrospective study

This study investigated changes in prenatal diagnostic indications among pregnant women in Heilongjiang Province, China, over a 10-year period (2014-2023) and evaluated the clinical efficacy of karyotype analysis and copy number variation sequencing (CNV-seq) for prenatal diagnosis.

We retrospectively analyzed data from pregnant women who underwent amniocentesis based on prenatal diagnostic criteria from January 2014 to June 2023 and provided consent, focusing on prenatal diagnostic indications, fetal chromosomal karyotype analyses, and CNV-seq results.

Among the 3,458 pregnant women, prenatal diagnosis indications included a high risk of NIPT (23.13%, 800/3,458) and a high risk of biochemical serological screening (22.30%, 771/3,458). Since 2017, the proportion of NIPT combined with fetal ultrasound abnormalities rose steadily, reaching 57.14% after 2020. Karyotype analysis was performed on 3,341 successfully cultured samples, revealing an abnormal karyotype detection rate of 18.25% (610/3,341). Structural chromosomal abnormalities accounted for 35.08% (214/610), followed by trisomy 21 (34.26%, 209/610) and sex chromosomal abnormalities (20%, 122/610). The overall positive predictive value (PPV) of NIPT was 44.40%, with a PPV for trisomy 21 of 81.72%. CNV-seq testing covered 2,771 samples, detecting pathogenic variations in 16.60% (460/2,771). Notably, 80 cases of pathogenic variation were identified in samples with normal karyotypes, and ​​14 cases were found in 108 samples without karyotyping. The highest pathogenic variation detection rate was observed in the NIPT high-risk group(42.21%, 320/758). Combining CNV-seq with other tests increased the anomaly detection rate to 20.36% (704/3,458), a 2.11% improvement over karyotype analysis alone.

In recent 10 years, prenatal diagnosis indications in Heilongjiang Province have shifted to a "​​NIPT high-risk + abnormal ultrasound​​" pattern. Combined karyotype and CNV-seq testing​​ achieves a 20.36% anomaly detection rate. NIPT enables non-invasive screening​​ for fetal chromosome aneuploidy, while CNV-seq - a key technology for accurate prenatal diagnosis - helps reduce birth defects.