Clinical analysis of umbilical cord torsion-related prenatal stillbirth

This study aims to investigate the high-risk factors and ultrasonic examination of umbilical cord torsion (UCT)-related prenatal stillbirth, with a specific focus on diagnostic challenges and clinical implications.

We retrospectively analyzed the electronic data of 108 pregnant women(after 1:2 age propensity score matching from an initial 424 cases) with UCT who delivered from January 2013 to February 2024 in Tongji Hospital, Tongji Medical College, University of Science and Technology. To mitigate confounding and address group imbalance, a 1:2 matching principle of the same age was performed (36 stillbirths vs. 72 live fetuses). Univariate and multivariate logistic regression analyses were used to identify independent predictors. Model performance was assessed by the area under the receiver operating characteristic curve (AUC), Hosmer-Lemeshow test, and Adjusted R². The diagnostic utility of prenatal ultrasound was comprehensively evaluated.

Analysis of the matched cohort confirmed balance in baseline characteristics and revealed seven significant associations. The multivariate model demonstrated excellent performance (AUC = 0.943, 95% CI: 0.895-0.991; Hosmer-Lemeshow P = 0.842). History of decreased or vanished fetal movement (OR = 64.337, 95% CI: 8.835-468.531, P < 0.001), umbilical cord root torsion at the fetal umbilical insertion site (OR = 24.426, 95% CI: 2.500-238.637, P = 0.006), and fetal growth restriction (FGR; OR = 13.292, 95% CI: 2.422-72.934, P = 0.003)were identified as the strongest independent predictors of UCT-related prenatal stillbirth. Other independent predictors (all P < 0.05) included: hydramnios (OR = 12.146, 95% CI: 1.684-87.620, P = 0.013); abnormal placental cord insertions (APCIs; OR = 0.050, P = 0.038, 95% CI: 0.003-0.841). Prenatal ultrasound exhibited a high specificity (93.1%) while a relatively weak sensitivity of 7.4% (95% CI: 3.3-14.2%), failing to detect 92.6% of UCT cases antenatally.

We developed and validated a highly accurate prediction model for UCT-related prenatal stillbirth, identifying a history of decreased or vanished fetal movement, umbilical cord root torsion at the fetal umbilical insertion site, and FGR as the paramount risk factors. Given the profound limitations of conventional ultrasound in prenatal detection, clinical management must undergo a critical shift: from reactive reliance on imaging to proactive management based on maternal symptomatology. Thus, decreased fetal movement should be the primary indicator for urgent assessment, while any sonographic suggestion of umbilical root torsion and FGR should trigger intensified surveillance and delivery planning.