An Update on Umbilical Cord Abnormalities and Associated Thrombosis: A Systematic Review

Background and objective: Umbilical cord abnormalities (UCAs) such as hypercoiling, velamentous or marginal cord insertion, or reduced Wharton's jelly are associated with umbilical thrombosis. UCAs increase the risk of vascular obstruction and impaired fetal blood flow, resulting in hypoxia or stillbirth. We examined the association between the UCAs and the umbilical cord thrombosis. Methods: According to PRISMA, five electronic databases (PubMed, Scopus, Embase, Cochrane Library, and Clinicaltrial.gov) were screened. Only studies that analyzed umbilical cord insertion abnormalities and abnormalities of the umbilical cord associated with thrombosis were included in this systematic review. Studies without thrombosis were excluded (PROSPERO ID: CRD420251087525). Results: Only 12 articles out of 1105 screened records satisfied the inclusion criteria, comprising 3 retrospective cohort studies, 3 case series and 6 case reports. The publication years ranged from 1983 to 2025. A total of 126 cases of umbilical vascular thromboembolism (UVTE) were identified, among which 84 cases of UCAs represented by 16 cases of stricture, 14 cases of hypercoiling, 16 cases of too-short cords (<= 40 cm), 11 cases of too-long cords (>= 70 cm), 5 cases of velamentous or furcate cord insertions, 12 cases of nuchal cord insertions, 13 cases of funistisis, 11 cases of true knots, and 3 cases of Wharton jelly abnormalities. Conclusions: UCAs, including true knots, abnormal coiling, and furcate or velamentous cord insertion, were highly associated with UVTE. Future studies should involve developing standardized criteria for the diagnosis and reporting of UCAs.