Nomogram to predict methotrexate treatment success in ectopic pregnancy

Abstract

ObjectiveTo evaluate clinical factors prior to methotrexate (MTX) treatment for tubal ectopic pregnancy and to apply the data to a prediction model for treatment success.MethodsA retrospective cohort study was conducted during 2014–2022. Of the 808 patients with a tubal ectopic pregnancy, 372 with a β‐hCG level less than 5000 IU/L were treated with a single dose of MTX and were included in this study. Pretreatment factors, including patient characteristics, initial β‐hCG level, and sonographic parameters, were compared between those who achieved complete resolution and those who needed additional MTX or surgical intervention. A logistic regression model and multivariable analysis were used to predict success. A graphic nomogram was generated to represent the model.ResultsComplete resolution of the ectopic pregnancy was achieved in 290 (77.9%) patients after a single dose of MTX. A second dose or surgical intervention was required for 82 (22.0%): 49 (13.2%) received a second dose of MTX and 33 (8.9%) underwent laparoscopic salpingectomy. In the MTX Success group compared to the MTX Failure group, the median β‐hCG levels were lower (746 vs 1347 IU/L, P < 0.001) and the presence of a yolk sac and a fetal pole were less frequent. The predictive model, based on significant variables, includes initial β‐hCG concentration and the visibility of a yolk sac or fetal pole. Analysis with cross‐validation techniques revealed that the model was both accurate and discriminative.ConclusionA predictive nomogram was developed to predict the success of single‐dose MTX treatment for tubal ectopic pregnancy.