Clinical Complications Induced by Placental Site Subinvolution: Secondary-Type Hemorrhage after Delivery and Pseudo Aneurysms after Non-Traumatic Delivery may be Caused by Atony Of The Uteroplacental Artery

Results: In postpartum hemorrhage cases, placental site subinvolution was diagnosed. Microscopic examination of the resected uterus showed subinvoluted arteries containing large thrombi. Immunohistochemical analysis showed that extravillous trophoblasts were present within the walls of subinvoluted vessels. Failure of involution on the placental site sometimes occurs following miscarriages as well. In post-miscarriage psudoaneurysms case, the distinctive hemorrhage in this patient consisted of bleeding from various sites in the myometrium after the placental chorion had been expelled without leaving a remnant. The bleeding pattern was extremely similar to the postpartum hemorrhage described above. Though, we could not confirm extravillous trophoblasts directly because of the succes of conservative treatment, these postpartum and post-miscarriage hemorrhage were thought to have the same pathophysiology.