The Effect of Three-dimensional Umbilical Cord Coiling Index on Obstetrical and Neonatal Outcomes: a Prospective Study

The umbilical cord connects the growing fetus to the placenta and contains 3 blood vessels, 2 arteries and a vein. The umbilical cord is protected by a layer of Wharton jelly and is characterized by being coiled. This coiling provides the umbilical cord with strength and flexibility simultaneously, and as a result lowers the risk of complications such as torsion of the umbilical cord.

The reason for the formation of this coiling is unknown, but there are many hypotheses such as mobility and rotation of the fetus around the axis of the umbilical cord, a different growth pattern of the blood vessels in the umbilical cord and a special arrangement of the muscles in the walls of the arteries of the umbilical cord.

Umbilical cord index (UCI) is the distance between one coil of the umbilical cord. it is calculated from the inner edge of the wall of an umbilical cord artery or vein to the outer edge of the same vessel in the next coil, the direction is from the edge of the placenta to the fetus. The final value is the average of three readings in three different segments of the umbilical cord.

Previous studies have shown that abnormal coiling of the umbilical cord is associated with adverse perinatal outcome. For example, an umbilical cord that is non-coiled increases the chance of fetal morbidity and mortality, moreover, they have shown that the lack of the usual coiled umbilical cord configuration may result in an umbilical cord that is structurally less able to withstand external mechanical stress, on the other hand, studies from recent years show that hypercoiling - excessive coiling of the umbilical cord is associated with poor obstetric outcomes, such as fetal distress at birth, meconium staining, fetal acidosis, premature birth, intrauterine growth disorder and even fetal death.

The studies carried out on the calculation of UCI include performing these measurements in two dimensions, including Doppler activation, but no studies were carried out in which three dimensions were used. The purpose of the study is to measure UCI using a 3D method in a random sample of 250 patients beyond 24 week of gestation, and to compare pregnancies with hypercoiling, hypocoiling or with a normal number of coils in terms of birth outcomes.