Aromatase inhibitor letrozole: a novel treatment for ectopic pregnancy

The aromatase inhibitor letrozole may be a safe and effective medical treatment of ectopic pregnancy compared with methotrexate.

VOLUME 114, ISSUE 2, P361-366


Mohamed F. Mitwally, M.D., H.C.L.D., Walaa G. Hozayen, Ph.D., Kamel M.A. Hassanin, Ph.D., Kamal A. Abdalla, M.D., Noha K. Abdalla, B.Sc.



To study the use of the aromatase inhibitor letrozole for treatment of ectopic pregnancy compared with methotrexate.


Nonrandomized prospective cohort study.


University hospital.


A series of 42 consecutive patients with undisturbed ectopic pregnancy.


Counseling on treatment options, including surgical treatment (control group) versus medical treatment with methotrexate (group 1) or letrozole (group 2).

Main Outcome Measure(s)

Primary outcome: complete resolution of ectopic pregnancy determined by serum human chorionic gonadotropin (β-hCG) levels below laboratory immunoassay detection. Secondary outcomes: changes in the biochemical parameter of ovarian reserve, antimüllerian hormone (AMH), and hematologic changes associated with the two medical treatments compared with surgical treatment.


Each treatment group included 14 patients, and each patient made her own treatment choice. Complete resolution of ectopic pregnancy occurred in an equal number of patients: 12 out of 14 (86%) in each of the two medical treatment groups. Methotrexate treatment was associated with statistically significantly higher liver enzymes and lower blood platelets count. The decline in β-hCG levels was faster in the letrozole group when compared with the methotrexate group. Three months after treatment, AMH levels were lower in the methotrexate group when compared with the letrozole and the surgery groups. However, the decline in β-hCG and AMH levels was not statistically significant.


To our knowledge, this is the first report in the literature on the success of letrozole for the medical treatment of ectopic pregnancy. The promisingly high resolution rate and better safety profile that letrozole has compared with a chemotherapeutic agent such as methotrexate should encourage further studies.

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