Received August 14, 2015
Accepted November 18, 2015

Objective: The aim of this study was to report our preliminary experience regarding the use of letrozole in men with obstructive azoospermia (OA) undergoing percutaneous epididymal sperm aspiration (PESA) for in vitro fertilization treatment using intracytoplasmic sperm injection (ICSI), who had a very low sperm recovery upon PESA and unsuccessful ICSI. Our hypothesis was that letrozole therapy could improve testicular function by increasing serum gonadotropins and T levels, stimulate testicle germ cells and, most importantly, that it enhanced the motile sperm count at a second attempt. Methods: We report on our preliminary experience with letrozole therapy in 11 men with OA, who failed to achieve pregnancy in the first PESA–ICSI and did not have spermatozoa cryopreserved for a second attempt. The patients received 3 months of letrozole at 2.5mg/day and underwent PESA–ICSI after 6.1±3.8 months. The patients were 48.6 ± 9.6 years old, and underwent at least two PESA procedures. We evaluated the total motile sperm count per PESA samples, as the increases in serum FSH, LH, and T levels after treatment. Results: All parameters increased significantly at 3 months following letrozole therapy for most patients. The total motile sperm count increased from 100 to 500% compared to the first PESA. Conclusion: Letrozole can be considered a reliable treatment to improve sperm recovery for men with OA undergoing PESA–ICSI cycles by increasing serum gonadotropins and testosterone (T) levels, and—most importantly—the motile sperm count.