OC15.06: Treatment of Caesarean scar pregnancy by ultrasound‐guided injection of methotrexate

To study safety, efficacy and indications of ultrasound-guided local injection of methotrexate (MTX) in the treatment of CSP. CSP patients treated in Chinese PLA General Hospital from 2008 to 2022 were retrospectively recruited. We investigated clinical information and imaging data of patients before treatment. The successful rate was observed. 107 CSP patients were included. There were 103 (96.26%) patients treated successfully, among them 12 (11.65%) received additional MTX injection. The treatment failed in 4 (3.74%) patients with surgery intervention. β-HCG in the successful group was 12636.00 (2009.00, 28138.00) IU/L and lower than the failed group significantly 36678.00(33076.25, 147204.30) IU/L, P value is 0.004. Patients received multiple injection of MTX had higher β-HCG than those injected once [9157.00(1390.80, 24888.60) vs 33260.00 (17048.50, 80124.50), P = 0.001]. Only one patient had the side effect and the liver transaminase elevated after therapy and improved several days later. Ultrasound-guided injection of MTX is a safe and effective modality to treat CSP patients with lower β-HCG. The change trends of β-HCG and presence of clinical symptoms including vaginal bleeding and abdominal pain should be monitored, additional injection of MTX or surgery intervention could be performed if necessary.