To evaluate the antenatal umbilical coiling index in second trimester of gestation by sonography and postnatal umbilical coiling index in relation to pregnancy outcome

Abstract

Background: The umbilical cord extends from the fetal umbilicus to the fetal surface of the placenta. Its diameter is 0.8 to 2.0 cm, with an average length of 55 cm and a range of 30 to 100cm. The umbilical cord is the life line of fetus as it supplies water, nutrients and oxygen. Its three blood vessels pass along the length of the cord in a helical or coiled fashion. A coil is defined as a complete 360o spiral course of umbilical vessels around Wharton’s jelly. The umbilical coiling appears to confer turgor and compression- resistant properties to the umbilical unit, producing a cord that is strong but flexible. An abnormal coiling index has been reported to be related to adverse perinatal outcome.Methodology: This prospective observational one year study was conducted on 250 women with singleton pregnancy, who were booked and scheduled to deliver at this institution. The antenatal umbilical coiling index (aUCI) done at 18 to 23 weeks of gestation. After delivery the UCI was determined. The sensitivity and the specificity of the sonography for detecting hypocoiling, normocoiling and hypercoiling was calculated. The correlation of aUCI and UCI with perinatal outcome were assessed and stastistical analysis done.Observations: It was observed that in aUCI group, there were 22 (8.8%) hypocoiled cords, 204 (81.6%) normocoiled and 24 (9.6%) were hypercoiled cords. In UCI group, there were 25 (10%), 200 (80%) and 25 (10%) cords in the hypocoiled, hypercoiled and hypercoiled groups respectively. The sensitivity of the sonography for detecting hypocoiling, normocoiling and hypercoiling was 84%, 98.5% and 80% respectively. The specificity of the sonography for detecting hypocoiling, normocoiling and hypercoiling was 99.5%, 86% and 98.2% respectively. There was no significant association of antenatal as well as postnatal coiling pattern compared with the mode of delivery. There was significant association of LBW, fetal distress and meconium staining with both hypocoiled and hypercoiled groups as compared to the nomocoiled group. Although the percentage of neonates admitted to the neonatal intensive care unit (NICU) were more in the hypocoiled and hypercoiled group as compared to the normocoiled group but not statistically significant.Conclusion: This study concludes that the hypocoiling and hypercoiling of the umbilical cord observed during fetal ultrasound anatomical evaluation in the second trimester is associated with small for gestation age neonates, fetal distress and low apgar scores and may have a bearing on increased interventional deliveries thus increasing the burden on NICU. This observation has been found to be similar to the umbilical coiling index at birth, thus it is suggested that second trimester ultrasound should include umbilical coiling index as one of the parameters of evaluation and this can be used as a potential predictor of adverse perinatal outcome.