The impact of gestational sac size on the effectiveness and safety of high intensity focused ultrasound combined with ultrasound-guided suction curettage treatment for caesarean scar pregnancy

Objective: To evaluate the correlation between the gestational sac size and the effect and safety of high intensity focused ultrasound (HIFU) combined with ultrasound-guided suction curettage for caesarean scar pregnancy (CSP). Methods: Seventy-six patients with CSP were enrolled. Based on their gestational sac size, patients were divided into three groups: Group 1 (n = 16, 10-20 mm), Group 2 (n = 28, 21-30 mm) and Group 3 (n = 32, >30 mm). All of them were treated by HIFU combined with ultrasound-guided suction curettage. Baseline characteristics, parameters and adverse events of HIFU, and intraoperative hemorrhage during ultrasound-guided suction curettage were recorded. Results: The median treatment time and average treatment intensity of HIFU in Group 3 were significantly higher than Group 1 (p < .05); the median HIFU treatment power in Group 2 and Group 3 were both significantly higher than that of Group 1 (p < .05). The median sonication time of HIFU in Group 3 was significantly longer than patients in the other two groups (p < .05). The size of the gestational sac had a positive correlation with all the above-mentioned parameters of HIFU and blood loss during ultrasound-guided suction curettage (p < .05). No statistically significant differences were observed among the three groups in the duration of vaginal bleeding post-curettage and the time necessary for serum beta-hCG to return to normal levels (p > .05). Conclusions: HIFU combined with ultrasound-guided suction curettage is a safe and effective clinical approach for CSP. Gestational sac size is a meaningful factor for predicting the efficacy and safety of HIFU treatment and hemorrhage during ultrasound-guided suction curettage.