Management of Viable Cesarean Scar Pregnancies (CSP) with Potassium Chloride (KCl) and the Requirement for Adjunctive Treatments

Introduction: Cesarean scar pregnancy (CSP) is a rare type of ectopic pregnancy that implants in or on the scar of a previous cesarean birth. The mechanism for implantation of a CSP is not completely understood. If left untreated, CSP can increase the risk of maternal complications such as uterine rupture, miscarriage, postpartum hemorrhage, and the development of placenta accreta spectrum. Potassium chloride (KCl) has been employed in the treatment of CSP as a conservative approach aiming to preserve the uterus and future fertility. Objective: To analyze the success rate and adverse outcomes associated with cases of viable CSP treated with KCl and requirement for adjunctive treatments. Methods: In this retrospective cohort study all viable CSPs treated cases were reviewed. Patient files were analyzed for demographic and clinical data. SPSS Version 22 was utilized for statistical analysis. Results: Twenty-two patients were treated, with a mean maternal age of 35.8 years (28– 43) and mean BMI of 31.4 kg/m 2 (20– 53). Successful resolution, defined by a decline of serum β-hCG to undetectable levels without surgical intervention, was achieved in 95.5% (21/22). Thirteen patients (59.1%) resolved with KCl alone. Adjunctive measures included KCl with systemic methotrexate were needed for five patients (22.7%) due to plateauing serum β-hCG levels. Two patients required adjunctive treatment with either uterine artery embolization (UAE), or systemic methotrexate and UAE. One patient (4.5%) after failed management with UAE and two doses of methotrexate, underwent secondary treatment with KCl injection that resulted in embryonic demise and a successful outcome. Follow-up was available for all 22 patients (100%), and complete resolution without major complications was confirmed. In conclusion, KCl is a reasonable approach as a first line management of viable CSP, however, patients should be aware of possibility of treatment failure and need for additional treatment measures. Plain Language Summary: KCl injection is an effective, fertility-preserving option for the management of cesarean scar pregnancy. It offers a minimally invasive, outpatient treatment that helps patients avoid the need for surgery and the complications associated with it. Keywords: cesarean scar, ectopic, pregnancy, KCl, embolization