Dynamics of placental and uterine blood flow: A functional index using ^113mIn

The dynamics of placental and uterine blood flow were investigated with Indium 113m in two groups of patients: Those with Rh incompatibility and those with uterine bleeding. The initial slopes of radioactivity entry into the placenta were greater than that for the myometrium. The placenta to myometrium ratios (P/M) were significantly higher in the presence of bleeding than in Rh incompatibility (4.84 ± 0.44 and 2.61 ± 0.50, respectively). Data were also analyzed using an exponential approach. It revealed that the ratio of half-time, for initial radioactivity for myometrium and placenta, was significantly higher in bleeders than in patients with Rh incompatibility. This approach may serve as a useful index of placental status.