Nonuniformity of fetal umbilical systolic/diastolic ratios as determined with duplex Doppler sonography.
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.
Kay
H H
HH
Department of OB/GYN, Duke University Medical Center, Durham, NC 27710.
Carroll
B A
BA
Bowie
J D
JD
Killam
A P
AP
Hertzberg
B S
BS
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