Abstract: Objective：To determine the risk factors for failture of an ectopic pregnancy（EP）with single-dose methotrexate. Methods：The clinical data of patients after a single-dose methotrexate for EP in Renmin Hospital of Wuhan University from July 2006 to July 2011 was reviewed retrospectively. Results：Two hundred and sixty-nine cases of EP were reviewed. The cases were divided into twogroups. One group（19.3%） were cases with ruptured EP and another group were 144 （80.7%） cases with unruptured EP. failure group and successful group according to the outcome. Fifty-two of them The mean level of pretreatment β-hCG，ratio of previous EP，mean gestation（in weeks），and size of the gestational mass were significantly higher in patients with ruptured EP compared with patients with unruptured EP（P＜0.05）. Logistic regression analysis revealed that 2 000～5 000 IU/L of pre-hCG level and≥5 000 IU/L of pre-hCG levels and also 6～8 weeks of amenorrhoea and >8 weeks of amenorrhoea and size of the gestational mass≥4 cm were the significantly risk factors for tubal rupture（P＜0.05）. No significantly associations existed regarding age，previous normal deliveries，previous induced abortion，prior pelvic surgery and use of an intra-uterine contraceptive device（IUD）. The receiver operating characteristic（ROC） curve cutoff value in the success group indicated an initialβ-hCG level of 1 871.5IU/L .At the value of 1 871.5 IU/L，sensitivity and specificity in the success group reached 82.7% and 70%. The area under the curve reached 0.8（P＜0.05）. Conclusions：Higher initial β-hCG level，higher gestational age and size of the gestational mass seem to be significant risk factors for failure of single-dose methotrexate therapy，Methotrexate should be used with caution in patients with EP.

Key words: Pregnancy, ectopic, Methotrexate, Risk factors, Logistic models, ROC curve