Objective: To explore the predictive value of the nomogram model constructed by color Doppler ultrasound parameters in the risk of hemorrhage during scar pregnancy (CSP) surgery. Methods: A retrospective analysis of the clinical data of 254 patients with pathologically confirmed CSP who were admitted to the Gansu Provincial Maternity and Child Health Hospital from September 2017 to September 2021. The patients were divided into two groups according to the bleeding volume during uterine cleaning and uterine/laparoscopic surgery

including 60 cases in the study group (bleeding volume ≥400ml) and 194 cases in the control group (bleeding volume <400ml). Compare the differences between the two groups of patients in clinical and ultrasound characteristics. Logistic regression was used to screen the risk factors of hemorrhage during CSP operation

and then a nomogram prediction model was constructed

and the prediction model was evaluated by calibration chart and ROC curve. Results: Compared with the control group

the thickness of the residual muscle layer of the patients in the study group was reduced (P<0.05)

the size of the lesions and the incidence of the abdominal pain

the mass lesion type

and the grade III blood flow classification were increased (P<0.05). Logistic regression analysis showed that abdominal pain

lesion size

residual muscle thickness

lesion type

and blood flow classification were risk factors for intraoperative hemorrhage in CSP patients (P<0.05). The nomogram calibration curve shows that the incidence of hemorrhage predicted by the model was in good agreement with the actual incidence. The area under the ROC curve of the nomogram prediction model was AUC=0.878 (95%CI: 0.831-0.926

P<0.05). Conclusion: The nomogram prediction model constructed by color Doppler parameters has a good predictive value for the risk of intraoperative hemorrhage in CSP patients.