Three-dimensional ultrasound does not improve diagnosis of retained placental tissue compared to two-dimensional ultrasound.

The study objective was to improve ultrasonic diagnosis of retained placental tissue by measuring the volume of the uterine body and cavity using three-dimensional (3D) ultrasound. Twenty-five women who were to undergo surgical curettage due to suspected retained placental tissue were included. The volume of the uterine body and cavity was measured using the VOCAL imaging program. Twenty-one women had retained placental tissue histologically verified. Three of these had uterine volumes exceeding the largest volume observed in the normal puerperium. Seventeen of the 21 women had a uterine cavity volume exceeding the largest volume observed in the normal puerperium. In all 14 cases examined 28 days or more after delivery the cavity volume exceeded the largest volume observed in the normal puerperium. A large cavity volume estimated with 3D ultrasound is indicative of retained placental tissue. However, 3D ultrasound adds little or no diagnostic power compared to 2D ultrasound.