Background: We propose to clarify the effect of umbilical arterial resistance on umbilical arterial blood flow patterns in normal pregnant women.
Subjects: Pulsed Doppler examination was administered to 145 pregnant women of between 28 and 31 weeks of normal gestation without any prenatal complications.
Methods: The arterial flow velocity waveforms from two different arteries, one in the intra-abdominal portion and the other at the placental insertion, were sampled with the color flow mapping method, and the peak systolic velocity and the resistance index were calculated.
Results: The peak systolic velocity and resistance index on the placental side were significantly lower than those of the fetal side.
Conclusion: A major difference exists between the umbilical arterial flow velocity waveforms on the fetal and placental sides, which might be caused by difference in the umbilical arterial resistance.