Umbilical artery waveform analysis based on maximum, mean and mode velocity in early human pregnancy

The objective of this study was to identify the best method for reconstructing blood-flow velocities from the early human umbilical artery to 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 velocity and heart rate in the umbilical artery, the maximum velocity reconstruction method is preferred because it is relatively insensitive to noise, nonuniform insonation, and wall filter settings. (C) 1998 World Federation for Ultrasound in Medicine & Biology.