The AVM is a rare congenital disease that often affects the brain and only rarely we find in other organs. In this pathology there is an alteration of the vascular system, with the arteries discharging directly into the veins, bypassing the capillary system; this puts the patient at high risk of sudden hemorrhage. Today we present the case of a young woman suffering from unknown pulmonary avm. The breakdown of this avm caused a hemothorax in the immediate post-cesarean, necessitating emergency surgery and subsequent intensive care.