Uterine arteriovenous malformations (UAVMs) that occur after birth are a rare cause of late postpartum hemorrhage. Acquired UAVMs usually occur in conjunction with pathology of the placenta. In the spectrum of placenta accreta (PAS), subinvolution of the placental bed plays an important role in its pathophysiology. We present a case of UAVM in a pregnant woman with PAS who presented with marked metrorrhagia after delivery, which was treated with classical management. Then, 35 days later, she presented to the emergency room with severe metrorrhagia. As it was suspected that she had placental remnants, an instrumental uterine control was performed, but the bleeding persisted, requiring further uterine packing and blood administration. Later, uterine artery embolization was performed with good results. Color Doppler ultrasound, magnetic resonance imaging, and angiography were the methods with the greatest diagnostic value. The differential diagnosis was as complex as the treatment. We hypothesize that UAVM may develop from minimal residual PAS in this late postpartum period. Moreover, they may recover rapidly after local surgical ablation. Considering the clinical condition, hemodynamic status, and desire to preserve fertility, we were able to avoid a hysterectomy, which is often chosen in such cases of severe, life-threatening bleeding complications.