Goh A, Karine P, Kirby A, et al. - In this retrospective cohort study, researchers examined whether determination of changes in Day 1 to Day 4 serum human chorionic gonadotropin (hCG) levels can aid in predicting treatment failure of single-dose methotrexate (MTX) in medical management of tubal ectopic pregnancies (EP). On reviewing 252 files for women who received at least one dose of 50 mg/m ² intramuscular MTX for treatment of ultrasound-confirmed tubal EPs, they included 108 in final analysis. Findings suggest potential predictive value of ≥ 5% rise in Day 1/4 serum hCG levels for treatment failure of single-dose MTX for tubal EPs, and conversely, suggest reliable predictive value of < 5% rise or any drop in Day 1/4 hCG levels for treatment success. Factoring-in Day 1/4 hCG changes could be considered during the course of medically managing patients. Clinicians must bear in mind, however, that acting on the Day 1/4 hCG change would result in increased interventions.