Fetal volume blood flow and umbilical artery flow velocity waveform analysis: a comparison.
The estimation of fetal umbilical vein and aortic volume blood flow was compared with umbilical artery flow velocity-time waveform analysis in 42 pregnancies. The volume blood flow measurements were made with a combined linear array B-mode and pulsed Doppler ultrasound system. The umbilical artery flow velocity-time waveform analysis was made with either pulsed or continuous wave 2 MHz Doppler ultrasound and the systolic/diastolic (A/B) ratio was used as an index of flow resistance. There was no difference when continuous wave was compared to pulsed Doppler ultrasound as a method of recording flow velocity waveforms. Analysis of the umbilical artery flow velocity-time waveform was more sensitive (100%-50%) than the measurement of umbilical vein volume blood flow (ml/kg/min) in the detection of the small-for-gestational age (SGA) fetus. The predictive value of a positive test was higher (71%-45%) while specificity was similar (88%-81%). Descending aortic volume flow was reduced in only one SGA fetus. The increase in umbilical placental downstream resistance (high systolic/diastolic ratio) was associated with a reduction in the percentage of fetal aortic blood flow directed to the umbilical placental circulation.
W B
WB
Giles
G
G
Lingman
K
K
Marsál
B J
BJ
Trudinger
D000328:Adult; D001011:Aorta; D001783:Blood Flow Velocity; D001810:Blood Volume; D005260:Female; D005312:Fetal Blood / Q000502:physiology*; D006801:Humans; D011247:Pregnancy; D011263:Pregnancy Trimester, Third; D014465:Ultrasonics; D014471:Umbilical Veins