Fetal intestinal dilatation and digestive tract abnormalities: an analysis of 94 cases from 16,090 deliveries in eastern Tianjin.

BACKGROUND: Prenatal detection of fetal intestinal dilatation (FID) presents significant counseling challenges, particularly in late gestation when the distinction between structural and functional causes guides clinical management. This study evaluated the diagnostic performance of prenatal ultrasound for distinguishing structural from functional gastrointestinal abnormalities in a large cohort with postnatally confirmed diagnoses. METHODS: A retrospective analysis was conducted on 16,090 deliveries at a single tertiary center from January 2021 to May 2025. Ninety-four cases with prenatal FID were identified and followed postnatally. Diagnostic performance metrics (sensitivity, specificity, predictive values) were calculated, and ultrasound characteristics were compared between structural and functional cases. RESULTS: Among 94 FID cases, postnatal follow-up confirmed 27 (28.7%) structural abnormalities and 67 (71.3%) functional disorders. Prenatal ultrasound showed moderate sensitivity (63.0%, 95% CI: 43.9-79.3%) but low specificity (24.2%, 95% CI: 13.9-38.2%) for detecting structural anomalies. Isolated FID in late gestation (≥33 weeks) could not reliably distinguish structural from functional causes, with comparable detection rates (63.0% vs. 76.1%, P = 0.148) and similar intestinal diameters (median 1.72 vs. 1.85 cm, P = 0.147) between groups. ROC curve analysis confirmed poor predictive value of intestinal diameter alone (AUC = 0.413). CONCLUSION: Isolated late-gestation FID has limited diagnostic specificity for structural gastrointestinal abnormalities, with high false-positive rates. These findings emphasize the need for cautious prenatal counseling and systematic postnatal evaluation. The proposed ultrasound assessment framework represents preliminary findings requiring prospective validation.