Myometrial Pseudoaneurysm and Myelosuppression Following Conservative Management of Caesarean Scar Ectopic Pregnancy.

Treatment of Caesarean 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.A 34-year-old woman was treated conservatively for a Caesarean 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.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 Caesarean scar pregnancy conservatively.