A pseudoaneurysm of the uterine artery or its branches is usually a result of vascular trauma during invasive procedures such as a cesarean section, vaginal delivery, myomectomy, hysterotomy, or dilatation and curettage. A uterine artery pseudoaneurysm rupture is a rare, yet life-threatening event. Deep infiltrating endometriosis usually involves a decrease in symptoms and imaging findings throughout pregnancy, with the notable exception of the phenomenon of decidualization. We present the case of a pregnant woman with a recent diagnosis of endometriosis, who conceived spontaneously and presented with disabling pain at 13 weeks’ gestation. She was diagnosed with a left, huge (and rapidly growing) retrocervical endometriosis nodule encompassing a uterine artery pseudoaneurysm. Selective transarterial embolization was performed at 22 weeks’ gestation owing to enlargement of the pseudoaneurysm sac, and the pseudoaneurysm was obliterated successfully. The patient was followed intensively throughout the pregnancy and the baby was delivered at term by cesarean section. After delivery, the nodule returned to the pregestational size.