Clinical Research Directory

Inclusion Criteria: * 18 years or older * Diagnosis of ectopic pregnancy * Desire for reproduction * Ease of return * Undetermined pregnancy location with abnormal hCG growth * Presence of a heterogeneous adnexal mass on pelvic ultrasound suggestive of a tubal ectopic pregnancy with an hCG level ≤ 3000 mIU/ml * Absence of fetal cardiac activity * Average diameter of the adnexal mass ≤ 3.5 cm * Hemodynamically stable * No significant abdominal pain (i.e, \< 6 on a visual analog scale) Exclusion Criteria: * Presence of a significant amount of free fluid in the pelvis (as assessed by the ultrasound technician) * Allergy to methotrexate or letrozole * A reduction in β-hCG ≥ 50% in 2 measurements with 48 hours between them or ≥ 85% in 4 days, or ≥ 95% in 7 days before randomization * Abnormal liver function test (Alanine transaminase (ALT) ≥ 2 times the upper limit of normal) * Abnormal renal function test (glomerular filtration rate ≤ 45 ml/min) * Hemoglobin \<10 g/dl * Platelets \<120.000/ml * Presence of heterotopic pregnancy * Do not wish to participate in the study.