The correlation between endometrial thickness and the criteria for MTX treatment for ectopic pregnancy

Ectopic pregnancy (EP) occurs in approximately 2% of all pregnancies. A common method of treatment is methotrexate therapy, considered in haemodynamically stable patients. Endometrial thickness has been investigated as a tool for diagnosing EP. The objective of this study was to evaluate the association between endometrial thickness and the criteria for MTX treatment, in an attempt to facilitate outcome prediction. We retrospectively collected data from records of patients diagnosed with EP between 2012 and 2014 including information regarding the mode of treatment and outcome. The endometrial thickness was compared between cases that met the criteria for MTX treatment and those who did not. Of 267 cases of EP that were reviewed, 108 patients were treated with MTX. The MTX treatment success rate was 88%. Endometrial thickness was found to be significantly and inversely associated with criteria for MTX treatment. In conclusion, an association was found between the endometrial thickness and the criteria for selection of MTX treatment for EP. This may be a useful tool in treatment selection for EP.Impact StatementWhat is already known on this subject? Transvaginal sonography along with β-human chorionic gonadotrophin (β-hCG) monitoring is the standard for evaluation of suspected ectopic pregnancy (EP). The most specific sonographic finding for EP is the presence of a live extra uterine pregnancy. In research conducted with the purpose of finding intrauterine sonographic findings associated with EP, this condition has been shown to be correlated with a thinner endometrial lining, compared with that of an intrauterine pregnancy.What the results of this study add? The results of this study add information on the subject of methotrexate treatment success rates in correlation with the endometrial thickness.What the implications are of these findings for clinical practice and/or further research? The findings of this study contribute to the process of treatment selection for ectopic pregnancy by emphasising the association between a thick endometrium and the lower success rates of MTX treatment.