Evaluation of umbilical cord thickness, cross-sectional area, and coiling index as predictors of pregnancy outcome

AIMS: This study was designed to evaluate the relationship of sonographic measurements of umbilical cord thickness, cross-sectional area, and coiling index with pregnancy outcome (low birth weight, 5-min Apgar score, and meconium staining). MATERIALS AND METHODS: From January 2010 to January 2011, among 255 singleton pregnant women who were referred for routine pregnancy USG after 20 weeks of gestation, 223 fulfilled the study criteria. In these patients, the diameter, cross-sectional area, and coiling index were measured in a free loop of umbilical cord. The pregnancies were followed till delivery, when birth weight, presence of meconium staining, and 5-min Apgar score were recorded. The sonographic measurements and clinical findings were analyzed to determine any correlation. RESULTS: A statistically significant correlation was observed between small umbilical cord thickness and cross-sectional area and low birth weight (LBW), with sensitivity of 52.9% and 57.9%, specificity of 95.0% and 94.4%, positive predictive value of 52.6% and 52.0%, and negative predictive value of 95.0% and 95.0%, respectively. Also noted was significant correlation between small umbilical cord thickness and cross-sectional area with meconium staining (P<0.001). No significant correlation was seen between umbilical cord thickness and cross-sectional area with low 5-min Apgar score. There was no statistically significant correlation between umbilical cord coiling index and LBW, 5-min Apgar score, and meconium staining. CONCLUSION: Umbilical cord diameter and cross-sectional area measured after 20 weeks of gestation are useful for predicting LBW and meconium staining and have the potential to serve as markers for adverse pregnancy outcome.