Modeling The Loss Of The Menstrual Cycle In AFAB Individuals Receiving Testosterone Replacement Therapy

Many transgender (trans) men and nonbinary AFAB (assigned female at birth) individuals choose to undergo testosterone replacement therapy, TRT, where they take exogenous testosterone (T) to bring about masculinizing changes in the body. One of these changes is the loss of the menstrual cycle. T has a negative feedback effect on the hypothalamic-pituitary axis (H-P axis) which dampens secretion of luteinizing hormone (LH). LH allows for secondary follicles to develop until the ovulatory phase and then prompts ovulation; therefore, as LH levels decrease, follicles are less likely to complete the ovulatory stage, thus disrupting the regular menstrual cycle. Our model explores the effects of varying dosages of T on the dynamics of the eventual loss of the menstrual cycle.