Hemorrhage into the cavity of the uterus. The three types of pathologic uterine hemorrhage are essential uterine hemorrhage (metropathia haemorrhagica), which occurs with pelvic, uterine, or cervical diseases; intrapartum hemorrhage, which occurs during labor; and postpartum hemorrhage, which occurs after the third stage of labor. The last may be caused by rupture, lacerations, relaxation of the uterus, hematoma, or retained products of conception, including the placenta or membrane fragments.