SYSTOLIC NOTCH IN UMBILICAL ARTERY FLOW VELOCITY WAVE-FORMS ASSOCIATED WITH A TIGHT TRUE KNOT OF THE CORD

True knot of the umbilical cord is a potentially lethal condition for the fetus. No specific diagnostic methods are currently available for detecting this ominous condition. A case of a tight true knot in the umbilical cord which presented with signs of acute fetal distress is described. Doppler velocimetry of the umbilical artery demonstrated a systolic notch and markedly decreased flow velocities during diastole. This pattern may reflect hemodynamic alterations in the feto-placental circulation secondary to narrowing of umbilical vessels, and can alert the obstetrician to the presence of this ominous condition.