title: Volumetric umbilical artery blood flow: comparison of the normal versus the single umbilical artery cord.
abstract: OBJECTIVE
  This was a study of the volumetric blood flow in single umbilical artery (SUA) cords as compared to three-vessel cords.
  
  
  OBJECTIVE
  SUA flow will be twice that of an artery in a normal cord.
  
  
  METHODS
  We studied 276 patients (24 SUA, 252 normal cord) at 18-40 weeks' gestation utilizing gray-scale and color Doppler. Flow, flow/kg, velocity, artery diameter, Doppler velocimetry indices, estimated fetal weight (EFW) and amniotic fluid index (AFI) were compared. All fetuses were anatomically and cytogenetically normal.
  
  
  RESULTS
  Blood flow increased with advancing gestation and the SUA volume was twice that in the normal cord artery. Flow/kg decreased for both cords, with the SUA values twice those of normal cords. Arterial diameter and velocity increased, but to a greater degree in SUA. Velocimetry, although in the normal range, decreased progressively with the resistance indices always lower in the SUA cord. EFW and AFI were the same for both groups.
  
  
  CONCLUSIONS
  Volumetric blood and its components were measured indirectly with ultrasound. The SUA cord artery carried twice the blood volume of an artery in a three-vessel cord. Other flow parameters changed appropriately to explain the increased flow. For the anatomically normal fetus with SUA there was no increase in intrauterine growth restriction.
authors.affiliation: Department of Obstetrics and Gynecology, Memorial Health University Medical Center, Savannah, Georgia 23089, USA.
authors.forename: J W
authors.initials: JW
authors.lastname: Goldkrand
authors.forename: C
authors.initials: C
authors.lastname: Pettigrew
authors.forename: S U
authors.initials: SU
authors.lastname: Lentz
authors.forename: S P
authors.initials: SP
authors.lastname: Clements
authors.forename: J L
authors.initials: JL
authors.lastname: Bryant
authors.forename: J
authors.initials: J
authors.lastname: Hodges
mesh_terms: D000328:Adult; D001783:Blood Flow Velocity; D005260:Female; D005865:Gestational Age; D006801:Humans; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D011263:Pregnancy Trimester, Third; D016216:Ultrasonography, Prenatal; D014469:Umbilical Arteries / Q000502:physiology*; D014470:Umbilical Cord / Q000002:abnormalities* / Q000000981:diagnostic imaging; D014599:Uterus / Q000098:blood supply*