Placenta
Nonneoplastic placental conditions and abnormalities
Umbilical cord
Single umbilical artery and supernumerary vessels


Topic Completed: 1 November 2011

Minor changes: 29 October 2020

Copyright: 2002-2020, PathologyOutlines.com, Inc.

PubMed Search: Single umbilical artery[title] "loattrfull text"[sb]

Mandolin S. Ziadie, M.D.
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Cite this page: Ziadie MS. Single umbilical artery and supernumerary vessels. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/placentasua.html. Accessed November 30th, 2020.
Single umbilical artery
  • Two vessel cord (usually are 3 vessels) with a single artery and a single vein (a hypoplastic artery may be present)
  • Remaining artery may be a persistent vitelline artery in cases of caudal regression / synringomelia
  • Diagnosed in 1% of placentas, with higher rates occurring with congenital anomalies, perinatal death and fetal growth restriction
  • Also more common in maternal diabetes
  • No increased risk of postneonatal mortality
Supernumerary vessels
  • Four or more umbilical cord vessels due to an extra artery or vein
  • May be associated with fetal anomalies and maternal smoking
  • Thought to originate from persistent umbilical veins or vitelline vessels
  • Looping may cause artifactual supernumerary vessels and should be excluded on gross examination
Gross description
  • Evaluation of vessel number should be performed away from the disc due to the possibility of umbilical artery anastamoses / fusion in this location
  • Single umbilical artery associated with higher incidence of abnormal cord (velamentous) and membrane (circumvallate) insertion
Microscopic (histologic) images

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Two vessel umbilical cord

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