Umbilical venous pulsation associated with hypercoiled cord in growth-retarded fetuses.

Venous pulsatile flows were detected by pulsed Doppler flow velocimetry throughout the entire umbilical cord in 2 cases of intrauterine growth retardation. Although the hearts of these fetuses had no anomalies and their inferior vena cava flows had normal flow velocity patterns, their cords were severely coiled. In these cases, the pulsatile flow in the umbilical cord vein was caused not by an increase in the preload of the fetal heart, but only by hypercoiling of the umbilical cord. This phenomenon also suggests that the coiled umbilical cord exerts a pump-like effect known as a 'pulsometer'.