Thrombosis is one of the serious complications related to prophylactic balloon occlusion of the abdominal aorta (PBOAA). This study aims to retrospectively analyze the efficacy and safety of continuous low-flow infusion of diluted heparin saline to prevent this complication related to PBOAA and further to provide the theory and evidences for using PBOAA.A study was carried out at our hospital from March 2016 to December 2018. Women with pernicious placenta previa (PPP) were treated PBOAA to prevent massive bleeding during CS. According to whether continuous low-flow infusion of diluted heparin saline was used to prevent catheter-related thrombosis or not, they were divided into 2 groups, the test group and the control group. The incidence of thrombosis between the 2 groups was compared and the effective treatment of thrombosis was also discussed. The comparison of nonparametric values was accomplished by using Fisher exact test. Statistical significance was set at P < .05.There were 31 women with PPP who received PBOAA during CS who were included in our study. Six of 19 women in control group (31.6%) developed thrombotic complications, while none of 12 women in test group. There were statistically significant differences in the incidence of thrombosis between the 2 groups (P = .037). There was no statistically significant difference in the amount of estimated blood loss and blood transfusion during CS between the 2 groups, nor was there statistically significant difference in the hospital days after CS (P > .05). All 6 women with thrombotic complications had no positive symptoms and thrombotic sequelae. The managements of thrombus included systemic anticoagulation, catheter-directed thrombolysis, and catheter-directed anticoagulation. One of the 6 women was lost to follow-up, and the thrombus of the other 5 women were completely dissolved. No other adverse outcomes or complications related to PBOAA were observed in all women in this study.Continuous low-flow infusion of diluted heparin saline is a safe procedure when PBOAA is performed for patients with PPP. It can effectively reduce or even avoid thrombosis without increasing intraoperative blood loss during CS for PPP patients.