Abstract: AIM: To evaluate the therapeutic efficacy and failure factors in single dose methotrexate intramusculr injection in treatment of ectopic pregnancy. METHODS: The clinical data of 70 successfully treated cases and 10 failed cases were analyzed comparatively, including the duration of menoschesis, serum β-HCG level, diameter of adnexa mass and abdominal pain before treatment as well as the decline rate of serum β-HCG level and change of mass diameter after 3 d of treatment. RESULTS: In succeeded group, the average duration of menoschesis, the mean level of serum β-HCG and average diameter of adnexa mass were 53 ±5 d (14.3 % of patients ≥60 d), 1483 ±216 IU·L^-1 (11.4 %of patients ≥4000 IU·L^-1) and 2.9 ±0.9 cm(7.9 % of patients showed increase of mass diameter ≥25 %), respectively; whereas in failed group, these corresponding figures were 62 ±6.d(40.0 %), 6661 ±126 IU·L^-1 (80.0 %), 4.1 ±0.6 cm (40.0 %), respectively.After 3 d of treatment, 14.3 % of patients in succeeded group revealed a decline rate of serum β-HCG level ≤15 %, while 60.0 % of patients in failed group revealed a similar decline rate. CONCLUSION: Methotrexate is an effective drug for treating ectopic pregnancy in its early stage.The serum β-HCG level before treatment, its decline rate and the change of adnexa mass diameter after 3 d of treatment are closely related to the therapy failure.Presence of fetus heart beating is not a contraindication for drug treatment of ectopic pregnancy.

Key words: methotrexate TU, pregnancy, ectopic DT, treatment failure