Abstract: Objective To retrospectively analyze the outcome of different treatment methods for cesarean scar pregnancy (CSP), to explore the key factors affecting the outcome of CSP treatment, and to establish a quantitative pre-scoring system in clinical practice. 
Methods In total, 240 patients with CSP who were treated for the first time in the Second Hospital of Hebei Medical University were retrospectively analyzed. Patients were divided into three groups according to their treatment methods, namely, ultrasound-guided uterine clearance group, uterine packing group and laparoscopic surgery (or laparotomy) group. Clinical and auxiliary examination data and treatment success rate of patients in each group were compared to find out the factors affecting the treatment outcome. The optimal scale regression method and mathematical model in statistics were used to calculate the weight of each influencing factor and assign its value. The quantitative pre-evaluation score table of CSP risk was established to carry out preliminary verification. 
Results The differences in six variables, including the maximum diameter of the gestational sac, ultrasonic classification, thickness of the remaining muscle layer, blood flow classification, fetal heart beat and β-human chorionic gonadotropin (β-HCG level) in the clinical and ultrasonic characteristics of the patient were statistically significant (P＜0.05). The weights of the predictive value of each influencing factor in the treatment outcome were residual muscle layer thickness (50.3%), ultrasonic classification (15.0%), blood flow grade of pregnancy sac (12.4%), the maximum diameter of pregnancy sac (11.1%), presence or absence of fetal heart beat (7.1%), and preoperative blood β- HCG level (4.1%). A quantitative scoring system was established accordingly and converted into a 10 point system. The consistency test showed that the actual treatment mode was basically consistent with the predicted treatment mode, and the Kappa coefficient was 0.637. 
Conclusion The influencing factors for the outcome of CSP treatment were residual myometrial thickness, ultrasound classification, blood flow grade of pregnancy sac, the maximum diameter of gestational sac, presence or absence of fetal heart beats and preoperative β-HCG values. A quantitative scoring system based on the weight of the above influencing factors in the overall risk can predict the severity of CSP and the surgical plan to be selected. 

Key words: pregnancy, cesarean cection, scoring system, risk factors