Successful oocyte cryopreservation using letrozole as an adjunct to stimulation in a transgender adolescent after GnRH agonist suppression

To report a successful case of ovarian hyperstimulation and oocyte cryopreservation in a transgender male adolescent after suppression with a gonadotropin-releasing hormone (GnRH) agonist while using the aromatase inhibitor letrozole to maintain low serum estradiol.Case report.Division of Reproductive Endocrinology and Infertility, Washington University in St. Louis School of Medicine, St Louis, Missouri.A 15-year-old Tanner II transgender male adolescent with a GnRH agonist implant.The GnRH agonist implant was removed. The patient was given letrozole (5 mg daily) while undergoing ovarian stimulation with an antagonist protocol. After oocyte retrieval, the patient began taking testosterone.Successful oocyte cryopreservation with minimal changes in breast budding.The patient's peak serum estradiol concentration was 510 pg/mL. Twenty-two mature oocytes were cryopreserved. Small increases in breast budding occurred between baseline and the time of oocyte retrieval.We successfully used letrozole to maintain low serum estradiol in a transgender male adolescent during ovarian stimulation. Maintaining low estradiol to minimize pubertal development and possibly prevent gender dysphoria symptoms may make oocyte cryopreservation more desirable for transgender male adolescents.