Routine Β-HCG Monitoring for Single-Dose Methotrexate Treatment in Ectopic Pregnancy.

To evaluate an alternative monitoring protocol without D4 β-HCG measurement for predicting the need for a repeated methotrexate (MTX) dose in patients undergoing single-dose MTX therapy for ectopic pregnancy.Single center, Retrospective study (Canadian Task Force classification II-3).University-affiliated hospital.184 ectopic pregnancy patients who were treated with MTX between January 2009 and December 2016 were included in the study.Single-dose MTX treatment (50mg/m(2)) MEASUREMENTS AND MAIN RESULTS: The patients were treated with repeated doses of MTX every 7 days, if necessary, according to Stovall's protocol or with laparoscopic surgery in cases of tubal rupture. The success of a single-dose of MTX according to the alternative measure was defined as a >50% decrease in the β-HCG level between day (D) 1 and D7 in clinically stable patients. The sensitivity, specificity, false-negative rate, false-positive rate and attributable risk of this new monitoring measure were calculated and compared to the traditional regimen. The new protocol had a sensitivity and specificity of 100% and 88.7%, respectively, for predicting a required second dose in patients whose D1 β-HCG levels were <2000 mIU/mL. For patients with D1 β-HCG level ≥2000 mIU/mL, both monitoring regimens had the same efficiency.The new monitoring model without the D4 β-HCG measurement may offer both patients and clinicians multiple options to monitor single-dose MTX therapy for selected ectopic pregnancy patients, with a comparable clinical efficiency to Stovall's protocol and less expense and follow-up burden to patients.