title: Nonuniformity of fetal umbilical systolic/diastolic ratios as determined with duplex Doppler sonography.
abstract: Fetal umbilical arterial systolic/diastolic (S/D) ratios are said to be uniform throughout the umbilical cord. We evaluated this phenomenon by performing duplex Dopper on 73 fetuses at three sites in the umbilical cord: near the placental origin, in the free-floating midcord, and near the fetal abdominal wall insertion. Twenty-one of 73 fetuses examined (29%) demonstrated pronounced nonuniformity of the S/D ratios with a discrepancy of 1 or greater between any two S/D measurements. Studies demonstrated the highest S/D ratios at the fetal abdominal wall and lowest S/D ratios at the placental origin. These findings suggest that umbilical arterial flow velocity waveforms (FVWs) and S/D ratios are not uniform throughout the cord in all patients. The significance of this finding is uncertain; however, this variability in umbilical cord flow velocity waveforms stresses the importance of identifying the portion of the umbilical cord from which S/D ratios are obtained.
authors.affiliation: Department of OB/GYN, Duke University Medical Center, Durham, NC 27710.
authors.forename: H H
authors.initials: HH
authors.lastname: Kay
authors.forename: B A
authors.initials: BA
authors.lastname: Carroll
authors.forename: J D
authors.initials: JD
authors.lastname: Bowie
authors.forename: A P
authors.initials: AP
authors.lastname: Killam
authors.forename: B S
authors.initials: BS
authors.lastname: Hertzberg
mesh_terms: D001783:Blood Flow Velocity; D005260:Female; D006801:Humans; D009200:Myocardial Contraction; D011247:Pregnancy; D012039:Regional Blood Flow; D014465:Ultrasonics; D014463:Ultrasonography; D014469:Umbilical Arteries / Q000502:physiology*; D014470:Umbilical Cord / Q000098:blood supply