Introduction Postpartum uterine bleeding is a common occurrence in the field of Obstetrics and varies in severity from harmless to life- threatening. The majority of the cases are due to atony, retained tissue or lesions in the birth canal, making up more than 99% of the cases. However, rare causes, such as structural abnormalities and coagulopathies, are important to keep in mind during diagnostics, when the common causes of postpartum bleeding are ruled out, particularly when the symptoms present in an unconventional manner. Methods A case report of a healthy woman presenting with acute life-threatening postpartum bleeding due to an acquired arteriovenous malformation of the uterus. Results A 43-year-old healthy woman presented with acute life-threatening gynecological bleeding 16 days after acute caesarean section. Ultrasound raised the suspicion of arteriovenous malformation. However, due to uncertainty of the diagnosis no initial treatment was preformed until the patient presented with heavy bleeding once more, resulting in a life-saving hysterectomy. Conclusion Arteriovenous malformation is an important diagnosis to consider, as early and effective diagnostics brings the opportunity for a safe and fertility-preserving treatment in the form of radiological coiling embolization. Advances in ultrasound skills of clinicians has made fast and bedside diagnostics possible, therefore the number of hysterectomies should decrease in favor of fertility-preserving treatment.