Arteriovenous Malformations (AVMs) | Boston Children’s Hospital

Learn more: Arteriovenous Malformations (AVMs) are abnormal connections between arteries and veins that are congenital (present at birth). They don’t have the normal network of tiny vessels (capillaries) that connects arteries and veins. Intracranial (within the head) AVMs have no visible symptoms. However, they may cause headaches or sudden bleeding into the brain. AVMs are relatively rare birth defects. They occur approximately once in every 500 births. AVMs are m