Pharmacological treatment of ectopic pregnancy: Accuracy, safety and cost‐effectiveness of day 1–7 β‐hCG measurements

Objective The aim of the present study was to compare accuracy, safety and cost‐effectiveness of three β‐hCG measurements protocols, applied in managing ectopic pregnancies (EP) with methotrexate (MTX): (1) day 1 to 7 β‐hCG levels, (2) day 1 to 4 β‐hCG levels and (3) day 4 to 7 β‐hCG levels. Methods Cost‐minimization analysis (CMA) based on a retrospective study of patients treated with single‐dose MTX for EP, was evaluated at a single institution between January 2001 to May 2021. Successful MTX treatment was defined as no surgical intervention. We evaluated safety by analyzing cases of day 4 interventions and cases of inconsistency between the different protocols. Predicting accuracy was assessed by the area under the receiver operating characteristic (AUC) curve. Results A total of 229 patients with single dose MTX treatment were included. Overall, 184 (80.3%) patients were treated successfully with a single dose of MTX. For days 1 and 7 the optimal cutoff point was 7% reduction in β‐hCG levels with sensitivity, specificity and PPV of 76.6% (69.9–82.5, 95% CI), 75.5% (60.5–87.1, 95% CI) and 92.8% (88.4–95.6, 95% CI), respectively. There was no significant difference between the protocols' AUC. None of the patients had any change of management during their day 4 visit in our 20 years of records. The cost for each visit day (day 4 and 7) was calculated with a total cost of 251 USD per patient. Conclusion Patients treated with MTX for EP, measurement of day 1 and day 7 β‐hCG serum levels has a cost minimization advantage and is not inferior to the traditional protocol for predictive accuracy and safety. Synopsis Patients treated with methotrexate for ectopic pregnancy, measurement of day 1–7 β‐hCG levels has cost minimization advantage with no decline in safety or accuracy.