title: Venous flow through coiled and noncoiled umbilical cords. Effects of external compression, twisting and longitudinal stretching.
abstract: OBJECTIVE
  To examine the association between umbilical cord coiling and perinatal morbidity.
  
  
  METHODS
  Ten umbilical cord segments, six coiled and four noncoiled, were categorized according to Strong's coiling index and were examined experimentally. The umbilical arteries and vein were perfused, pressurized, placed in a saline bath at 37 degrees C and subjected to compression, twisting and stretching while measuring venous flow.
  
  
  RESULTS
  There was no statistically significant difference in umbilical venous flow between coiled and noncoiled cords when external compression, twisting and longitudinal stretching were applied to the cord segments.
  
  
  CONCLUSIONS
  Differences in morbidity associated with umbilical cord coiling should not be attributed simply to mechanical factors, and other mechanisms should be sought.
authors.affiliation: Department of Obstetrics and Gynecology, Loyola University Medical Center, Maywood, Illinois, USA.
authors.forename: G M
authors.initials: GM
authors.lastname: Dado
authors.forename: P B
authors.initials: PB
authors.lastname: Dobrin
authors.forename: R S
authors.initials: RS
authors.lastname: Mrkvicka
mesh_terms: D001696:Biomechanical Phenomena; D001783:Blood Flow Velocity; D003250:Constriction; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D010477:Perfusion; D011247:Pregnancy; D011312:Pressure; D014470:Umbilical Cord / Q000098:blood supply / Q000502:physiology*; D014471:Umbilical Veins / Q000502:physiology*; D014655:Vascular Resistance