Different umbilical artery flow velocity waveforms in one patient.

Serial studies of umbilical artery flow velocity waveforms in one patient revealed two quite distinct waveforms at each study. The mean systolic/diastolic ratio difference between the studies was 2.2 units. After delivery, the placenta was seen to include a large infarcted lobule supplied by only one of the umbilical arteries. The finding of two very dissimilar umbilical artery flow velocity waveforms at the time of study should raise the suspicion of placental infarction, but management decisions should be based on the most normal study.