(145) Testosterone Levels in Transgender Women After Gender Affirming Surgery

Abstract Introduction Gender-affirming surgeries (GAS) are critical in alleviating gender dysphoria among transgender women (TGW), yet their impact on postoperative hormone levels and sexual health remains incompletely understood. Testosterone is central to sexual desire, but little data exist on serum testosterone after transfeminine bottom surgery. Objective To describe serum testosterone and estradiol levels among TGW after bottom surgery and explore associations with postoperative sexual function. Methods We conducted a retrospective cohort study using the TriNetX US Collaborative Network, encompassing 62 healthcare organizations. Patients with at least one testosterone measurement within six months before and/or any time after transfeminine bottom surgery were included. Analyses compared (1) mean testosterone and estradiol levels between patients with only pre- versus only postoperative measurements, and (2) within-patient changes among those with both. Hormone values were summarized as mean ± SD with ranges, and Welch’s t-tests assessed group differences. Results We identified 67 patients with only preoperative testosterone levels (mean age 39 ± 13 years), 94 with only postoperative levels (39 ± 11 years), and 39 with paired measurements (38 ± 11 years). Mean preoperative testosterone was 102 ± 147 ng/dL (range 3-560), compared with 38.1 ± 106 ng/dL postoperatively (range 1-831, p = 0.001). Within paired analyses, testosterone decreased from 70.3 ± 101 ng/dL preoperatively to 31.2 ± 81 ng/dL postoperatively (p = 0.032). Estradiol levels showed no significant differences between pre- and postoperative groups. Conclusions Transfeminine bottom surgery is associated with a significant decrease in serum testosterone, while estradiol remains stable. This decline may help explain reduced sexual desire reported by some TGW postoperatively. Clinical implications include the need for testosterone monitoring, patient counseling on potential changes in sexual function, and exploration of testosterone add-back therapy in symptomatic individuals. Prospective studies with validated patient-reported outcomes are needed to guide evidence-based care. Disclosure No.