ABSTRACT
BACKGROUND: Treatment of cesarean scar pregnancy is based on clinical context. This report describes two rare complications of conservative management: non-steroidal anti-inflammatory drug-induced methotrexate myelosuppression and myometrial pseudoaneurysm. CASE: A 34-year-old woman was treated conservatively for a cesarean scar pregnancy with systemic methotrexate and intragestational potassium chloride, resulting in pancytopenia secondary to concurrent non-steroidal anti-inflammatory drug use. She presented again with a myometrial pseudoaneurysm, which was treated with bilateral uterine artery embolization and, ultimately, hysterectomy. The final pathology report confirmed a pseudoaneurysm, retained villi within the myometrium, and acute endometritis and myometritis. CONCLUSION: Myelosuppression resulting from use of non-steroidal anti-inflammatory drugs affecting renal excretion of methotrexate can occur at low dosages. Additionally, there is a risk of pseudoaneurysms with vascular damage and trophoblastic tissue. Drug interactions and procedure-related risks must be considered when managing cesarean scar pregnancy conservatively.