Relationship between pitch value or S/D ratio of torsion of cord and fetal outcome

Abstract

To evaluate whether applying pitch values at different positions of the umbilical cord or the umbilical artery blood flow systolic/diastolic (S/D) ratio measured by color ultrasound could forecast excessive torsion of cord and help in selection of the appropriate mode of delivery. This study included 184 pregnant women between 37 and 41 weeks of gestation and their neonates. We analyzed the umbilical cord's spiral distance, and the umbilical artery blood flow parameters at the cord's initial section, middle section and the section into the placenta. We also examined the fetal umbilical cord after birth, performed blood gas analysis of umbilical cord blood and recorded the neonatal Apgar score. Excessive torsion of cord diagnosed by ultrasound and in postnatal anatomy had the same rate of 91%. With lower pitch values (<2.0) and higher S/D ratios (>3.0), the possibility of fetal distress was increased, the neonatal Apgar score was decreased and umbilical blood pH values < 7.2 were more common. Pitch values and blood flow S/D ratios in different sections of the umbilical cord measured by color ultrasound could forecast excessive torsion of cord and have great significance in reducing the perinatal death rate caused by umbilical cord factors.