Arteriovenous malformation (AVM) refers to a rare condition where instead of normal capillary plexus interaction between an artery and vein, there is an abnormal connection that leads to potential instability at that junction.

AVM can occur anywhere in the vascular system but can be of particular concern when it occurs in the uterus. This abnormal linkage can lead to significant issues related to abnormal uterine bleeding and potentially life-threatening bleeding when encountered in the operating room or at time of delivery.

AVMs are classified as idiopathic or acquired. Idiopathic AVMs are mostly congenital while acquired AVMs are secondary to episodes that have altered the uterine anatomy, eg, pregnancy / delivery, uterine surgery (including dilation and curettages, myomectomies, and cesarean deliveries), cervical / endometrial cancers, trauma, gestational trophoblastic disease, and possible exposure to diethylstilbestrol (DES). Etiology for secondary acquisition is unknown but is thought to be related to directed angiogenesis following injury to uterine tissues.

Typically, acquired AVMs are found in multiparous women of childbearing age. They often present with intermittent, large amounts of abnormal uterine bleeding. However, a large number of uterine AVMs are asymptomatic and may be incidental findings while undergoing evaluation for other conditions or encountered during surgery or after delivery.