Although transcatheter uterine artery embolization has been proved to be a life-saving technique in serious obstetrical hemorrhage, it does not always control bleeding. The causes of treatment failure may be multifactorial and vary in individual cases, but incomplete embolization of the blood supply from other sources may play an important role. Herein, the authors describe eight patients with massive postpartum hemorrhage that was not controlled with conventional hypogastric-uterine artery embolization. Their continued hemorrhage was due to an additional blood supply arising from ovarian arteries, which was confirmed with selective ovarian artery angiography and subsequently successfully embolized.