The umbilical cord and its vessels morphological and functional variability intrapartum analysis

A number of umbilical cord morphometric parameters, including its circumference, umbilical vessel diameters, umbilical cord area, umbilical arteries and veins, and embryonic mucosal connective tissue, are not subject to mandatory ultrasound examination. However, assessing these morphometric parameters during the antenatal period could help predict the outcome of labor. The aim of the study was to evaluate the impact of labor on the morphological and functional parameters of fetal umbilical vessels during full-term pregnancy. A total of 150 pregnant women participated in the study. The examination was conducted using a Samsung Accuvix XG 2019 ultrasound machine during the active phase of labor during contractions and 2-3 days before the onset of labor. The following anatomical and functional parameters were recorded: umbilical cord circumference in the proximal, median, and distal segments; internal diameters of the right and left umbilical arteries and vein in three similar segments; pulsatility index; maximum systolic blood flow velocity; and end-diastolic blood flow velocity. The cross-sectional areas of the umbilical cord, arteries, veins, and embryonic mucosal connective tissue were calculated. Statistically significant differences were found in maximum systolic and end-diastolic blood flow velocities, and consequently, in the pulsatility index. According to the nonparametric Wilcoxon test, umbilical cord circumference, internal diameters of umbilical vessels, and cross-sectional areas undergo statistically insignificant changes. The volume of embryonic mucosal connective tissue has a greater influence on umbilical cord circumference and cross-sectional area. With a normal umbilical cord anatomical structure, the intrapartum period proceeds without complications, despite fluctuations in hemodynamic parameters. Morphological parameters, namely, umbilical cord circumference in the proximal, medial, and distal segments; the internal diameter of the right and left umbilical arteries and vein in three analogous segments; the cross-sectional areas of the umbilical cord, arteries, and vein; and the embryonic connective tissue mucosa, retain their structure during the intrapartum period despite initially normal anatomical structure. The obtained results can be used as predictors for assessing birth outcomes.