International Journal of Biomedical Science and Research
True Umbilical Cord Knots: Navigating the Clinical Dilemma Through Current Evidence on Pathophysiology, Advanced Pre-natal Diagnosis, And MaternalâFetal Outcomes
Abstract
Chijioke Ogomegbunam Ezeigwe, George Uchenna Eleje, Gerald Tochukwu Igwemadu, Emmanuel Chukwubuikem Egwuatu, Emmanuel Onyebuchi Ugwu, Akaninyene Eseme Ubom, Chigozie Geoffrey Okafor, Adanna Vivian Egwim, Chukwudubem Chinagorom Onyejiaka, Charlotte Blanche Oguejiofor, Malarchy Ekwunife Nwankwo, Chukwunwendu Aloysius Okeke, Isaiah Chukwuebuka Umeoranefo, Odigonma Zinobia Ikpeze, Joseph Ifeanyichukwu Ikechebelu and Ahizechukwu Chigoziem Eke
Background: A true umbilical cord knot (TUCK) is a structural anomaly formed when the fetus slips through a cord loop during early gestation. While many cases follow a benign course protected by Wharton’s jelly, mechanical tightening can constrict the fetoplacental circulation, causing acute ischemia, hypoxia, and sudden intrauterine fetal demise. However, current clinical guidelines lack standardised management algorithms for prenatally diagnosed TUCK. This stems from a critical research gap: standard two-dimensional (2D) ultrasound fails to reliably detect the condition, while advanced three-dimensional (3D), four-dimensional (4D), and Doppler imaging criteria are not universally defined. Consequently, clinicians lack objective data to differentiate benign knots from high-risk, occlusive structures.
Objectives: This review evaluates the epidemiological footprint, pathophysiological drivers, and feto-maternal impacts of TUCK, aiming to resolve modern management controversies by exposing diagnostic limitations and establishing an evidence- based framework for prenatal monitoring.
Methods: A comprehensive narrative review was executed across PubMed, SCOPUS, web of Science, Google Scholar, and the Cochrane Library. Clinical trials, case series, and observational study datasets were synthesised to analyse risk profiles, diagnostic imaging sensitivity, and the clinical dilemma of balancing expectant management against iatrogenic intervention.
Results: TUCK occurs in 0.3%–1.3% of singleton pregnancies, showing structural associations with advanced maternal age, multiparity, polyhydramnios, and long umbilical cords (>70cm). Standard two-dimensional ultrasound yields an exceptionally poor antepartum detection rate (approximately 0.08%), highlighting a massive diagnostic blind spot in routine prenatal care. Conversely, targeted active scanning during the 17th to 26th week gestational window utilising colour Doppler and 3D/4D High-Definition Flow imaging achieves a diagnostic accuracy of ≥89.3%, identifying critical haemodynamic indicators like the “hanging noose” sign and persistent umbilical artery flow notches. Clinical tracking reveals distinct dual risks: tight structural constriction carries a 4-to-10-fold increase in stillbirth, chronic hypoxia, and intrapartum variable decelerations prompting emergency caesarean section. Conversely, prenatal diagnosis frequently operates as a powerful driver of subjective clinical risk, generating severe maternal anxiety and provider apprehension that inadvertently drive iatrogenic prematurity rates to 14.2% due to a lack of clear, conservative management protocols.
Conclusion: Universal screening for TUCK is counterproductive due to static imaging limitations and psychological burdens. Management of an incidentally discovered TUCK should avoid prophylactic early birth in stable cases. By synthesising disparate diagnostic data and highlighting the dangers of defensive medicine, this review provides the justification for individualised, outpatient expectant surveillance pathways for TUCK to safely maintain the pregnancy to term, reserving continuous electronic fetal monitoring exclusively for the intrapartum period.