OR11-3 Evidence for Preserved Ovarian Reserve in Transgender Men Receiving Testosterone Therapy: Anti-Mullerian Hormone Serum Levels Decrease Modestly after One Year of Treatment

Background: Although successful pregnancies carried by transgender men have been reported, long-term effects of testosterone therapy on fertility remain unknown. Aims: To study markers of ovarian reserve during testosterone therapy. Methods: Prospective open-label study of transgender men prior and during treatment with testosterone. Sampling was conducted at baseline and 12 months after treatment initiation. Main outcome measures: Anti-Mullerian Hormone (AMH), gonadotropins and sex steroid serum levels; endometrial thickness and antral follicular count determined by pelvic US. Results: 52 subjects (23.4±6.1 y) were recruited, 32% of which were in a stable relationship. 17% expressed desire to have children while 26 (50%) were unsure about future parenthood. Four (7%) have already undergone fertility preservation procedures. Interestingly, 5 participants (9%) that initially were sexually attracted to women became bisexual under testosterone treatment. Complete data is available for 32 subjects. In the course of 12 months of treatment, AMH levels decreased from 5.65±0.52ng/ml at baseline to 4.89±0.65 ng/ml (p=0.036). Antral follicular count (16.9±1.4, 13.9±1.7) and endometrial thickness (6.9±0.7, 5.6±0.5 mm) remained unchanged. As expected, testosterone levels increased (0.84±0.1, 7 ±0.7 nmol/l; p<0.0001) and estradiol levels decreased (90.8±7.9, 55.4±4.6 pmol/l; p=0.0013) during therapy, with a concomitant decrease in LH (7.56±0.7, 3.8±0.6 mIU/ml; p=0.0012), but not FSH (5.1±0.41, 4±0.3; p=0.07 mIU/ml) levels. Conclusion: AMH levels slightly decrease during testosterone treatment but remain within the normal, "healthy" range, thus likely indicating well-preserved ovarian reserve. This assumption is corroborated by the unchanged antral follicular count. The significance of these findings on fertility potential remains to be explored. Unless otherwise noted, all abstracts presented at ENDO are embargoed until the date and time of presentation. For oral presentations, the abstracts are embargoed until the session begins. Abstracts presented at a news conference are embargoed until the date and time of the news conference. The Endocrine Society reserves the right to lift the embargo on specific abstracts that are selected for promotion prior to or during ENDO.