Use of Letrozole for Ectopic Pregnancy

This is a multicenter randomized clinical trial on the use of letrozole in the medical treatment of tubal ectopic pregnancy. Tubal ectopic pregnancy is an abnormal pregnancy in the fallopian tube. They occurred in about 8% of all pregnancies presenting to the emergency department. Methotrexate (MTX), administered systemically (intramuscularly), is a widely used medication for the treatment of unruptured tubal ectopic pregnancies and has been recommended as first-line treatment for early cases of ectopic pregnancy.

Letrozole is an aromatase inhibitor and can suppress estradiol levels. Some recent studies have shown that its use can be applied in cases of ectopic pregnancy.

The aim of this non-inferiority clinical trial is to verify that letrozole treatment is non-inferior to methotrexate treatment in women with early ectopic pregnancy who are hemodynamically stable.

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.