Ultrasound-guided intralesional methotrexate injection as the first-line treatment of cesarean scar pregnancy

Abstract

Introduction: The objective of this study was to determine the outcome of using ultrasound-guided intralesional methotrexate injection as the first-line treatment of cesarean scar pregnancy (CSP). Methods: A review of literature obtained from the PubMed electronic database published in English from inception to December 2014, using the search words ‘cesarean scar’, ‘caesarean scar’ or ‘uterine scar’, ‘ectopic pregnancy’ or ‘pregnancy’ and ‘methotrexate’, supplemented by additional articles obtained from reference lists. Only those reports using ultrasound-guided intralesional methotrexate (with or without potassium chloride) injection as the first-line treatment of CSP with relevant outcome data were included in the review. Results: 96 cases from 95 women reported in 17 articles were reviewed. In 1 article consisting of 22 cases, only statistical data without individual case information were available. The mean age was 33.9 ± 4.4 years. The mean gestational age at the time of treatment was 6.8 ± 1.3 weeks (range 4.5–12 weeks). 34 women (45.9%, n = 74) had more than 1 previous cesarean sections. The median interval between the last cesarean section and the CSP was 4 years (range 0.5–13 years). The median serum hCG level prior to treatment was 24 080 IU/L (range 587–205 321 IU/L). Fetal cardiac activity was present in 49 of 72 women (68.1%). Of the 96 cases, 71 (73.9%) were successfully treated after single intralesional injection. The addition of potassium chloride with methotrexate in 11 cases did not improve the success. 14 cases achieved resolution after additional intralesional or intramuscular methotrexate administration giving an accumulated success rate of 88.5%. 11 cases required additional surgical interventions including: dilatation and curettage (D&C) or evacuation (3 cases); hysteroscopy (1); uterine artery embolization ± D&C (3); and laparotomy ± hysteroscopy (4). Woman's age, gestational age at diagnosis, number of previous cesarean sections, and sonographic visualization of fetal cardiac activity had no impact on the success rate of single or multiple methotrexate injection(s) of CSP. However, women with higher serum hCG level (>100 000 IU/L) were more likely to require surgical intervention (OR = 40.7, P = 0.002). Conclusions: The use of ultrasound-guided intralesional methotrexate injection could be considered as the first-line treatment of CSP with a success rate of 73.9% for a single intralesional injection. With further administration of methotrexate, an accumulative success rate of 88.5% could be achieved without the need for further surgical intervention. However, for women with high hCG levels, alternative treatment options should be considered.