Overestimation of umbilical cord coiling index with segmental versus total length assessment

The umbilical cord is the only communication between the fetus and the placenta and, not surprisingly, lesions or conditions affecting it may have detrimental effects in both. One important feature of the umbilical cord is its coiling index (UCI), with hypo- and hypercoiling being associated with fetal thrombotic vasculopathy, intolerance of labor, intrauterine growth restriction, cord stricture, thrombosis of cord and chorionic blood vessels, and fetal demise. It is essential that every placenta report include the UCI. The UCI could also be assessed prenatally, but there is currently no way of accurately assessing the entire length of the umbilical cord. The aim of this study was to compare UCI measured in a segment of cord 10 cm long (UCI-10) and over its total length (UCI-T). One hundred fifty consecutive placenta reports in which both measurements were recorded were retrieved from the files and analyzed. Gestational age ranged from 16 to 42 weeks, with a mean of 33.67 ± 5.96 weeks and a median of 36 weeks. Mean UCI-10 was 0.4360 ± 0.2625 coils/cm and mean UCI-T was 0.3530 ± 0.2022 coils/cm; the difference between these measurements was highly statistically significant (P < 0.0001). Counting the number of umbilical cord coils in 10 cm led to an overestimation of the UCI-T by 23.5%; it can be concluded, therefore, that the latter should be used.