Androgen Effects on the Reproductive Neuroendocrine Axis, 2025 Version

Testosterone Replacement Therapy (TRT) is the mainstay of gender affirming care for transgender men (TGM) who have male gender identity after female sex assignment at birth. TGM receiving TRT over time exhibit irregular menstrual bleeding, however, the mechanism of menstrual disruption is unknown. Therefore, the investigators propose to evaluate the effect of chronic testosterone (T) exposure on ovarian hormones and pituitary gonadotropin release that determines menstrual cyclicity. The investigators will conduct a detailed study of blood reproductive hormone secretion in TGM before and during TRT as well as in untreated cisgender female (CGF) control subjects who report female gender identity congruent with female sex assignment at birth. The investigators will also perform periodic clinical and ultrasonographic evaluations.

Inclusion criteria

Transgender/Non-binary Group, Initiating Testosterone Group

• Provision of signed and dated informed consent form
• Stated willingness to comply with all study procedures and availability for the duration of the study
• Aged 18-35
• Plan to initiate testosterone therapy
• History of regular menstrual cycles (every 24-35 days) at baseline, before beginning TRT

Inclusion criteria

Cisgender Female Group

• Provision of signed and dated informed consent form
• Stated willingness to comply with all study procedures and availability for the duration of the study
• Aged 18-35
• Having regular menstrual cycles (every 24-35 days)

Exclusion criteria

All

• Pregnant
• Incarcerated
• Known cognitive impairment or institutionalized
• Hemoglobin less than 11 gm/dl at screening evaluation
• Weight less than 110 pounds
• BMI <18 or >35
• Current endocrine disease- including untreated thyroid abnormalities, pituitary or adrenal disease, polycystic ovary syndrome, or androgen producing tumor
• Current or recent pregnancy within two months of study enrollment
• Current or recent breast feeding within two months of study enrollment
• Diabetes, or renal, liver, or heart disease
• History of oophorectomy or hysterectomy
• History of radiation or surgery involving brain structures and/or pelvis/pelvic organs
• Currently taking any medications that may affect their reproductive hormones, such as contraceptive medications, androgens, estrogens, progestins, gonadotropin-releasing hormone (GnRH) antagonists, insulinomimetics, and metformin.
• History of prior testosterone therapy