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. Part I: The Use of the Umbilical Artery Doppler in High- and Low-Risk Patients. First use of Doppler ultrasonography to study flow velocity in the fetal umbilical artery was reported in 1977Fitzgerald and Drumm. Non-invasive measurement of human circulation using ultrasound: a new method. BMJ
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9. Observational Studies:
Association between reduced end-diastolic umbilical artery velocities and increased vascular resistance in the fetoplacental circulation
17. Trudinger et al 1987
McPharland et al 1988
Hofmeyr et al 1991
Newham et al 1991
Burke et al 1992
Almstrom et al 1992
44. Blood supply provided by the ovarian and uterine arteries
Uterine Arteries: main branches of the internal iliac arteries
Uterine Arteries: Ascend through the lateral wall and anastomose with the ovarian arteries
48. Component 1: Pulsatile Waveform
Component II: Steady Waveform
49. Pulsatile Component: Formed by the interaction of an outgoing and reflected wave, which bounces back to the heart upon reaching the uteroplacental vascular bed
50. Increased Resistance
Decrease Mean Velocity
Elevated PI
Development of a notch in the early diastolic portion of the velocity waveforem caused by destructive interaction between outgoing and reflected waves
51. Decrease Uterine Artery Radius
Increase Mean Velocity
Elevated PI and S/D
NO DIASTOLIC NOTCH
52. Increase Mean Arterial Pressure
Elevation in mean velocity
NO change in RI or S/D
NO DIASTOLIC NOTCH