title: Qualitative estimation of blood velocity changes in human umbilical arteries after delivery.
abstract: Qualitative doppler shift ultrasound estimations of blood velocity were made from umbilical arteries of 17 neonates for 90 sec after delivery using a 10 MHz doppler instrument. The mean maximum doppler shift frequency at 10 sec was 1.5 kHz +/- 0.3 (SE) reducing to 0.5 +/- 0.1 kHz at 60 sec after delivery. This indicates that flow velocity cannot be quantified. The initial mean pulsatility index was 10.6 suggesting that either constrictions were occurring in the arteries by 10 sec after delivery or that the placenta has a high impedance or both.
mesh_terms: D001783:Blood Flow Velocity; D004301:Doppler Effect; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D011247:Pregnancy; D012212:Rheology; D014465:Ultrasonics / Q000295:instrumentation; D014463:Ultrasonography; D014469:Umbilical Arteries / Q000502:physiology*