Prognostic factors for spontaneous resolution of an ectopic pregnancy

Objective: To identify factors that can accurately predict the spontaneous resolution of an ectopic pregnancy. Study design: This retrospective cohort analysis was conducted in the Department of Gynecology of a tertiary, university-affiliated medical center. Patients admitted to the center from January 2015 to July 2022 with a tubal ectopic pregnancy who met the criteria for expectant management were included. Beta-human chorionic gonadotropin (ß-hCG) levels were assessed at admission and at subsequent 24-hour intervals. Patients with declining levels were discharged for routine ambulatory ß-hCG follow-up until levels became undetectable. Patients who achieved a successful outcome were designated as the “spontaneous resolution group,” while patients who underwent further hospitalization for methotrexate or surgery constituted the“ failure group”. Demographic, clinical, laboratory, and ultrasound parameters collected at first admission were compared between groups. Results: Among the initial group of 210 eligible patients, 7 were lost to follow-up, 161 achieved spontaneous resolution, and 42 were readmitted for active intervention. Multivariate logistic regression analysis revealed that the last ß-hCG level before discharge (last ß-hCG) and the ratio between ß-hCG at discharge to ß-hCG at admission were the only independent parameters to predict outcomes. Patients with ß-hCG < 650 IU/L at discharge and a decline of 50% or more in ß-hCG level during hospitalization, had a 97% success rate with expectant management. Patients with ß-hCG discharge levels ≥ 1,000 IU/L had a 50% chance of success, regardless of whether their ß-hCG levels had declined. For all other patients, a 76% success rate was found. Conclusion: Short-term, serial ß-hCG follow-up at the initial presentation can help predict the spontaneous resolution of an ectopic pregnancy.