Uterine artery Doppler ultrasound in postpartum women with retained placental tissue.

We measured prospectively uterine artery Doppler flow resistance indices and looked for hyper-vascular areas in 20 patients who were to undergo surgical evacuation due to clinical and ultrasound-based suspicion of retained placental tissue (RPT). We compared these findings with those of the normal puerperium. All 20 patients underwent surgical procedures. Placental tissue was histologically confirmed in 19 patients. Mean pulsatility and mean resistance values were below the 10th percentile for eight and seven women, respectively, but overlapping was extensive. A hyper-vascular area was observed in 12 patients with histological confirmation. In eight cases, six of them with histological confirmation, no hyper-vascular area was observed. Although RPT is associated with lower resistance indices in the uterine arteries, this knowledge has limited value as a diagnostic tool for RPT. Absence of a hyper-vascular area in the myometrium does not exclude RPT, but its presence is common finding associated with RPT and should not be misinterpreted as an arterio-vascular malformation.