Risk factors for intra-operative haemorrhage and bleeding risk scoring system for caesarean scar pregnancy: a case-control study.

OBJECTIVES

To investigate risk factors associated with excessive intra-operative haemorrhage during evacuation operation, and to develop a bleeding risk scoring system in patients with caesarean scar pregnancy (CSP) to guide treatment.

STUDY

DESIGN

A case-control study was conducted. Excessive intra-operative haemorrhage was defined as active bleeding during dilation and suction evacuation (blood loss ≥200ml). The bleeding group consisted of patients who experienced excessive intra-operative blood loss. Patients with less intra-operative blood loss were included in the control group.

RESULTS

In total, 458 admissions from 2009 to 2014 were included in this study. Compared with the control group, the bleeding group had higher serum β-human chorionic gonadotrophin (hCG), higher gestational age, larger CSP mass, richer peritrophoblastic perfusion and thinner myometrial layer before evacuation (all p<0.05). Risk factors with p<0.05 on multivariable logistic regression analysis included serum β-hCG >20,000mIU/ml [odds ratio (OR) 1.4, 95% confidence interval (CI) 1.0-3.2], gestational age >8 weeks (OR 2.1, 95% CI 1.1-4.0), maximum diameter of gestational sac or CSP mass ≥5cm (OR 7.4, 95% CI 3.4-16.1), myometrial thickness ≤0.15cm (OR 3.6, 95% CI 1.9-6.9) and significant peritrophoblastic perfusion (OR 9.8, 95% CI 4.1-23.2). These risk factors formed the final bleeding risk scoring system by conversion of their OR values into corresponding points. A total of 10 points was identified as the optimal cut-off on the receiver operating characteristic curve. Thus, patients with scores ≥10 points were identified as being at high risk of bleeding. The final bleeding risk scoring system had an area under the curve of 0.86, sensitivity of 86.8% and specificity of 73.2%.

CONCLUSIONS

Gestational age, serum β-hCG, size of gestational sac, thickness of myometrial layer and peritrophoblastic perfusion were found to be associated with excessive intra-operative haemorrhage during suction evacuation of CSP. A bleeding risk scoring system was constructed to help guide the management of patients with CSP. Patients with total scores ≥10 points were identified as being at high risk of bleeding, whereas patients with total scores ≤5 points were identified as being at low risk of bleeding.