Enhanced Myometrial Vascularity: Is It an Arteriovenous Malformation? Review of Definitions, Imaging Findings, and Management.

Enhanced myometrial vascularity (EMV) is a common postpregnancy (ie, postpartum, postpregnancy termination, and postpregnancy loss) sonographic finding that represents involuting myometrial hypervascularity of the placental bed in the early puerperium and may persist if retained products of conception (RPOC) are present. On color Doppler US images, EMV is characterized by tortuous and dilated myometrial vessels with high-velocity and turbulent flow. These features can be easily mistaken for an arteriovenous malformation (AVM). However, despite sharing overlapping flow patterns, AVM and EMV are fundamentally distinct. AVMs are vascular congenital malformations, whereas EMV is a dynamic finding in the postpregnancy state related to persistent or involuting uteroplacental circulation. Most EMVs that come to medical attention regress spontaneously after expulsion of the associated RPOC. AVMs, on the other hand, are not associated with pregnancy, do not regress spontaneously, and are difficult to treat, often requiring repeated embolization sessions with liquid embolic agents. By becoming familiar with EMV, radiologists may better serve patients and referring clinicians with guidance for further investigation or treatment (when appropriate), thereby preventing unnecessary interventions, hysterectomies, or potential complications associated with such treatments. The authors clarify the definitions of EMV, AVM, and other pertinent terms, discuss the physiology of the uteroplacental circulation and postpregnancy EMV, address the pathogenesis of persistent EMV associated with RPOC, and provide an overview of the imaging features and management of EMV. ©The Author(s) 2026. Published by the Radiological Society of North America under a CC BY 4.0 license. Supplemental material is available for this article. See the invited commentary by Kirsch and Ponder in this issue.