Predictors of Success of a Single-Dose Methotrexate in the Treatment of Ectopic Pregnancy

Background: Ectopic pregnancy (EP) is the commonest cause of maternal mortality-related death in the first trimester. Methotrexate (MTX) remains the first-line treatment in optimally selected patients. Objective: To evaluate the success rate and predictors of success of a single-dose MTX treatment in EP. Subjects and Method: We studied retrospectively 109 patients with unruptured EP who were treated with Intramuscular MTX administered in a dose of 50 mg/m2 on days 0 and in additional doses on day 7 if β-hCG levels did not decrease by 15 % during the follow-up period. The study was conducted at the Maternity and Children Hospital Buraidah, Saudi Arabia from June 2013 to December 2013. Pretreatment β-β-hCG, EP mass diameter, peritoneal fluid, and fetal cardiac activity were evaluated. The main outcome measures were success rate, the predictors of success without surgical treatment. Result: Under this regime, the overall success rate was 60.6 % of patients. Of the failure group, only 4.7 % of patients experienced rupture of EP. No side effects were reported. The main predictors of failure were initial β-hCG value ≥ 3.500 mIU/mL OR 4.11 (1.646–12.248, 0.043) and EP diameter 3.73 (1.646–12.10, p = 0.003). Conclusion: The success rate of MTX in this study was 60.6 %, and the initial β-hCG concentration and EP diameter were the best predictors of successful treatment with MTX. Furthermore, MTX should be offered only to those patients with β-hCG <2,000 mIU/mL and EP mass size <3.5 cm. © 2015, Federation of Obstetric & Gynecological Societies of India.