Background: Nowadays, ectopic pregnancies can be diagnosed early, and medical treatment with methotrexate instead of surgery is being used more often than in the past. No study of the success rates and predictive factors of single-dose methotrexate in management of ectopic pregnancy have previously been performed in Rajavithi Hospital.
Objective: To determine the success rates and predictive factors of single-dose methotrexate in treatment of ectopic pregnancy.
Material and Method: A retrospective study was conducted of ectopic pregnant women treated with methotrexate at Rajavithi
Hospital between 1st January 2011 and 31st May 2015. Successful treatment was defined as a decrease in serum beta-hCG levels to less than 5 mIU/ml with no need for further methotrexate or surgical treatment. Data collection and analysis of serum beta-hCG levels at pre-treatment (day 0) and post-treatment (days 4 and 7) were performed in all the subjects.
Results: In total, 106 ectopic pregnant women were initially treated with single-dose methotrexate, and seventy-two cases (67.9%) had successful outcomes. There was no association between patient characteristics or clinical presentations with success rates, with the exception of history of previous ectopic pregnancy (success group 4.2% vs. failure group 17.6%, p = 0.020). Median serum beta-hCG level at day 0 was significantly different between the success and failure groups (1,511 and 2,466 mIU/ml respectively, p = 0.040). A pre-treatment serum beta-hCG level of below 5,000 mIU/ml was the significant predictive factor for success based on multivariate logistic analysis (adjusted odds ratio 3.33; 95% CI, 1.18 to 9.40; p = 0.023).
Conclusion: Ectopic pregnant women with pre-treatment serum beta-hCG levels below 5,000 mIU/ml were the best candidates
for methotrexate treatment.

Keywords: Beta-hCG, Ectopic pregnancy, Methotrexate, Success rate