Performance Evaluation of Noninvasive Prenatal Testing in the Enshi Region: A Single-Center Retrospective Study

BACKGROUND Noninvasive prenatal testing (NIPT) is widely used, yet its real-world performance for sex chromosome aneuploidies and rare autosomal trisomies in understudied regional populations remains unclear. We evaluated NIPT’s screening accuracy and effects of maternal age, adverse obstetric history, and fetal nuchal translucency (NT) thickness in a regional cohort from Enshi. MATERIAL AND METHODS NIPT data and follow-up diagnostic outcomes for pregnant women at Central Hospital of Enshi Tujia and Miao Autonomous Prefecture (December 2020 to October 2023) were analyzed. Screening performance was evaluated. RESULTS Among 174 screen-positive cases (0.93%), 124 underwent invasive diagnosis, confirming 47 true positives and yielding an overall positive predictive value (PPV) of 37.90%. Common trisomies, sex chromosome anomalies, and other autosomal anomalies PPVs were 64.52%, 35.42%, and 22.22%, respectively. High-risk results for trisomy 7 and 45,X accounted for 35.63% of all positives but had low PPVs (13.33%, 17.24%). Detection rates were highest for class III obesity (6.25%), advanced maternal age (0.44%), and multiple adverse pregnancy histories (0.42%). PPV and detection rate increased with advancing maternal age and fetal NT thickness, reaching 66.67% and 0.9%, respectively, in women aged 40-44 years, and 71.43% and 0.84%, respectively, with NT of 2.0-2.5 mm. Assuming true negativity of screen-negative cases, estimated sensitivity and specificity exceeded 99% for every abnormality type; these estimates are conditional and should be interpreted with caution. CONCLUSIONS NIPT showed high PPV for common trisomies, moderate PPV for sex chromosome aneuploidies, and low PPV for other autosomal anomalies, with a particularly low PPV for 45,X. Maternal age, adverse pregnancy history, and increased NT were associated with a higher risk of fetal chromosomal abnormalities.