Risk factors for massive hemorrhage during the treatment of cesarean scar pregnancy: a systematic review and meta-analysis

Purpose Cesarean scar pregnancy (CSP) is one of the serious complications associated with cesarean delivery (CD). This meta-analysis aims to identify risk factors associated with massive hemorrhage during the CSP treatment. Methods Eight electronic databases were searched for case-control studies published before December 31th, 2018, which compared the possible factors causing massive bleeding during the CSP treatment. Quantitative synthesis was performed by RevMan 5.3. Sensitivity analysis and publication bias were performed by Stata 12.0. Results Total 20 case - control studies including 3101 CSP patients with previous CD met the inclusion criteria. Bleeding group had 573 patients and the control group had 2528 patients. The risk factors for massive bleeding during CSP treatment included multiple gravidities (MD = 0.15, 95% CI 0.03-0.28, P = 0.73), big maximum diameter of gestation sac (MD = 18.49 mm, 95%CI 15.34-21.65, P < 0.01), high gestational days (MD = 8.98 days, 95% CI 4.12-13.84, P < 0.01), high beta-HCG level (MD = 21.39 IU/ml, 95% CI 7.36-35.41, P = 0.03; MD = 3.02 U/ml, 95% CI 0.21-5.84, P < 0.01) and rich blood flow around the lesion (OR = 6.73, 95% CI 3.93-11.51, P = 0.59). While, thick myometrium (MD = - 4.94 mm, 95% CI - 6.12 to - 3.75, P < 0.01) may be protective factor. Conclusions Multiple gravidities, big gestation sac, large gestational days, high serum beta-HCG level, abundant blood supply to pregnancy sac and thin myometrium maybe the risk factors for massive bleeding during the CSP treatment.