UMBILICAL ARTERY WAVE-FORM ANALYSIS BASED ON MAXIMUM, MEAN AND MODE VELOCITY IN EARLY HUMAN-PREGNANCY

The objective of this study was to identify the best method for recons tructing blood-flow velocities from the early human umbilical artery t o determine the physiological changes in fetal blood-flow velocity and heart rate, Pulsed Doppler recordings from the umbilical artery with a duration of approximately 7 s were made at 10-20 weeks of gestation, For reconstruction of the blood-flow velocity from the Doppler audio signal, the maximum (envelope), mean and mode frequency reconstruction methods were used, For the assessment of variability in blood-how vel ocity and heart rate in the umbilical artery, the maximum velocity rec onstruction method is preferred because it is relatively insensitive t o noise, nonuniform insonation, and wall filter settings. (C) 1998 Wor ld Federation for Ultrasound in Medicine & Biology.