Retrospective Analysis of Prenatal Diagnosis Results and Exploration of Screening Strategies for 137 Fetuses with Down Syndrome

Abstract

Objective: To analyze the detection of fetuses with Down syndrome in the Prenatal Diagnosis Center of Guigang Maternal and Child Health Care Hospital, Guangxi, evaluate the efficacy of different prenatal screening methods, and provide data support for optimizing regional prenatal screening and diagnostic strategies. Methods: A retrospective analysis was conducted on the chromosome karyotype analysis results of 6799 pregnant women who underwent invasive prenatal diagnosis in our hospital from January 2020 to July 2025. Clinical data of fetuses diagnosed with trisomy 21 (Down syndrome) were collected, and their pregnancy outcomes were tracked. Results: Among the 6799 pregnant women, a total of 137 fetuses with Down syndrome were detected. Karyotype analysis showed 131 cases of standard type (95.6%), 2 cases of Robertsonian translocation type (1.5%), and 4 cases of mosaic type (2.9%). All diagnosed fetuses underwent termination of pregnancy. The primary indications for prenatal diagnosis included high-risk non-invasive prenatal testing (NIPT) (highest proportion), abnormal ultrasound soft markers (such as increased nuchal translucency (NT) or absent/hypoplastic nasal bone), advanced maternal age, and high-risk serum screening. NIPT showed the highest positive predictive value for trisomy 21 (97.4%), significantly higher than serum screening (1.05%). The detection rate of trisomy 21 in advanced-age pregnant women (≥35 years) (3.30%) was higher than that in non-advanced-age women (1.45%), and the detection rate increased with maternal age. Conclusion: Actively performing invasive prenatal diagnosis for pregnant women with indications such as high-risk NIPT, advanced age, abnormal ultrasound soft markers, or high-risk serum screening can effectively improve the prenatal detection rate of Down syndrome, enabling early intervention and reducing the birth rate of affected children. The combined use of multiple screening methods (such as first-trimester ultrasound soft marker screening combined with NIPT or serum screening) and standardizing the prenatal diagnostic process for high-risk populations are key measures for preventing birth defects.