Navigating the rare intersection of endometrial ablation and cesarean scar pregnancy: a case report

Endometrial ablation (EA) is an established treatment for heavy menstrual bleeding in women who have completed childbearing. It does not provide contraception, and pregnancies occurring after EA may have serious complications. Cesarean scar pregnancy (CSP) presents an additional diagnostic and therapeutic challenge in women with previous cesarean deliveries. We report the diagnostic and therapeutic management of CSP in a 40-year-old woman with a history of menorrhagia, thermal balloon EA two years earlier, and two previous cesarean deliveries. She presented to the emergency department with delayed menstruation. Her serum beta-human chorionic gonadotropin (β-hCG) concentration was 12,764 mIU/mL. Transvaginal ultrasound identified a gestational sac involving the cesarean scar niche, with residual myometrial thickness (RMT) of 3.5 mm. The pregnancy was accessible hysteroscopically, and the patient initially preferred uterine preservation despite having no desire for future pregnancy. Hysteroscopic removal of gestational tissue with adjunctive curettage was performed. Initial recovery was uncomplicated, but she subsequently developed heavy vaginal bleeding. Repeat ultrasound showed a heterogeneous lesion at the scar measuring 22 × 25 × 30 mm, with RMT of 1.2 mm. Laparoscopic hysterectomy was performed. Histopathology supported the diagnosis of CSP and demonstrated a thinned, fibrotic scar niche without placenta accreta or malignancy. Follow-up over 12 weeks showed recovery without further complications. Pregnancy after EA requires prompt assessment of implantation location, particularly in women with previous cesarean deliveries. This case illustrates that an RMT above 3 mm and reassuring early postoperative findings do not ensure sustained success after hysteroscopic treatment. Management should consider scar anatomy, clinical findings and patient preferences, with continued surveillance for delayed bleeding and persistent pregnancy-related tissue.