title: Absence of a relationship between umbilical cord thickness and coiling patterns.
abstract: OBJECTIVE
  The purpose of this study was to evaluate a relationship between the umbilical cord thickness and cord coiling patterns during the fetal sonographic anatomic survey in the second trimester of pregnancy.
  
  
  METHODS
  This was a prospective study of 470 patients with singleton pregnancies who had a fetal anatomic survey with recorded umbilical coiling patterns between 18 and 23 weeks' gestation. The umbilical cord thickness was assessed as an umbilical diameter at the level of the fetal abdominal cord insertion and compared with the antenatal umbilical coiling index (aUCI), calculated as a reciprocal value of the distance between a pair of umbilical cord coils.
  
  
  RESULTS
  Three hundred twenty-one patients had adequate sonographic umbilical cord images and maternal demographic, antenatal, and labor data to meet inclusion criteria. The mean aUCI was 0.41 with 10th and 90th percentiles of 0.21 and 0.60, respectively. A total of 10.6% (34/321) and 9.3% (30/321) of patients were categorized as having hypocoiled and hypercoiled umbilical cords, respectively. The mean cord diameter +/- SD was 9.48 +/- 0.97 mm (range 7.0-12.5 mm). There was no statistically significant correlation between aUCI and umbilical cord thickness (P = .1164).
  
  
  CONCLUSIONS
  An aUCI, or umbilical coiling pattern, does not correlate with umbilical cord thickness. It appears that a lesser amount of the umbilical supportive tissue, mainly Wharton jelly, is not related to an increased umbilical cord coiling pattern.
authors.affiliation: Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Weill Medical College of Cornell University, 525 E 68th St, Suite M-704, New York, NY 10021 USA. mlp2001@med.cornell.edu
authors.forename: Mladen
authors.initials: M
authors.lastname: Predanic
authors.forename: Sriram C
authors.initials: SC
authors.lastname: Perni
mesh_terms: D003430:Cross-Sectional Studies; D005260:Female; D005865:Gestational Age; D006801:Humans; D011247:Pregnancy; D011446:Prospective Studies; D016216:Ultrasonography, Prenatal; D014470:Umbilical Cord / Q000033:anatomy & histology* / Q000000981:diagnostic imaging*