8575 Single Dose Methotrexate, Predicting Outcomes at Time of Second Dose

Abstract

<h3>Study Objective</h3> The single dose methotrexate protocol, which may include additional doses, is an accepted option for treating ectopic pregnancies. The objective of this study was to determine what percentage of patients administered a second dose of methotrexate fail this regimen and undergo laparoscopy. Additionally, we defined patient characteristics that may influence the decision to pursue surgery. <h3>Design</h3> Retrospective cohort study. <h3>Setting</h3> High volume academic, tertiary medical center. <h3>Patients or Participants</h3> Patients with an ectopic pregnancy from July 2011 to July 2021 that underwent medical treatment with single dose methotrexate 50 mg/m² IM and subsequently received a second dose of methotrexate. <h3>Interventions</h3> Laparoscopic tubal surgery for ectopic pregnancy. <h3>Measurements and Main Results</h3> Over 10 years, 167 patients were given a second injection of methotrexate following their initial methotrexate dose. Of those, 35/167 (21%) patients underwent surgery. In those who underwent surgery 12/35 (34.3%) had a ruptured ectopic pregnancy, of whom 5/12 (41.7%) had a significant hemoperitoneum (≥500 ml). In patients with a documented ultrasound prior to the second dose of methotrexate, 26 of the 94 (27.7%) women with an adnexal mass had subsequent surgery compared to 9 of the 68 (13.2%) without a mass, RR of 2.12 (P=0.03). No other demographic or surgical risk factors (i.e. BMI, smoking status, history of abdominal surgery, diabetes, or prior ectopic pregnancy) impacted the risk of undergoing surgical management. <h3>Conclusion</h3> Of all women receiving a second dose following planned single dose methotrexate therapy, 79% were successfully medically managed. Patients with an adnexal mass on ultrasound had more than double the relative risk of undergoing surgery (27.7%) and should be counseled accordingly.