The development of dynamic placental scintigraphy, employing IV injected Indium-113m and a computer-linked scintillation camera, has permitted determination of total uteroplacental blood flow. In order to assess the effects of epidural anesthesia for cesarean section on placental blood flow (PBF), the authors investigated 11 women scheduled for elective cesarean section whose placentas were located on the anterior uterine wall. An additional 13 women were employed to determine the extent of blood volume expansion produced by electrolyte preloading.