Performance evaluation of non-invasive prenatal testing in the Enshi region: a single-center retrospective study of 18,661 cases

This study evaluated the screening performance of Non-Invasive Prenatal Testing (NIPT) in the Enshi region by conducting a retrospective analysis of 18,661 pregnant women at the Enshi Tujia and Miao Autonomous Prefecture Central Hospital. Among the participants, 174 were identified as high-risk, yielding a screen-positive rate of 0.93%. Of these, 124 high-risk women underwent invasive prenatal diagnosis, confirming 47 true positive cases. The overall positive predictive value (PPV) was 37.90%. The PPVs for target chromosomal abnormalities, sex chromosome abnormalities, and other autosomal anomalies were 65.52%, 35.42%, and 22.22%, respectively. High-risk results for trisomy 7 and 45,X abnormalities accounted for 35.63% of all high-risk cases, but their PPVs were significantly lower (13.33% and 17.24%, respectively). Clinical indication analysis revealed that advanced maternal age, a history of multiple adverse pregnancies, and Class III obesity were associated with an increased risk of chromosomal abnormalities, with detection rates of 0.44%, 0.42%, and 6.25%, respectively. Both the PPV and detection rate of NIPT increased with rising maternal age and fetal nuchal translucency (NT) thickness. Specifically, an NT thickness of 2.0–2.5 mm was associated with a PPV of 71% and a detection rate of 0.84%. In summary, NIPT demonstrated strong screening performance for common chromosomal abnormalities, particularly T21, but had higher false-positive rates for 45,X and rare trisomies. Maternal age, pregnancy history, and fetal NT thickness significantly influenced the screening efficacy, offering insights for clinical practice.