SUN-136 Serum Prolactin Elevation in Adult Transgender Women on Estradiol is Uncommon: A Retrospective Chart Review

Abstract Disclosure: P. Gupta: None. T.B. Karatas: None. V. Tangpricha: None. Introduction/ Background: The Endocrine Society recommends that transgender individuals prescribed estradiol should have periodic measurement of serum prolactin levels due to elevated risk of hyperprolactinemia. While it is known that estradiol increases prolactin levels, the exact incidence and if there is a correlation that exists between serum prolactin and estradiol levels is not known. Specific Aim: The aim of this study was to assess incidence of prolactin elevation and any relationship between serum prolactin with serum estradiol levels in transgender individuals taking estradiol. Materials and Methods: This was a retrospective chart review. Charts were reviewed of transgender individuals receiving estradiol at a single academic medical center. Participants’ information on gender- affirming hormone therapy, use of anti-psychotics and anti- depressants, serum prolactin and estradiol levels and dates of lab draws were recorded. Linear regression analysis was used to measure the association between prolactin level and estradiol level Results: Sixty-seven (67) participants who were prescribed estradiol with at least one documented prolactin were included. A total of 103 serum prolactin and serum estradiol levels drawn at the same time were available to be analyzed. The mean age of the participants was 35.4 years (SD 13.8). The majority of the participants (38/67) were on oral 17 beta estradiol. The majority of the participants (46/67) were not on any anti-psychotics or anti-depressants. Only 6 prolactin levels (5.8%) were elevated > 20 ng/mL in 5 individuals and none were above 100 ng/mL. Only 1 out of these 5 individuals was on antipsychotics and had 2 consecutive prolactin elevations. There was no significant relationship between serum estradiol and serum prolactin levels (R= 0.18, p=0.068) on linear regression analysis. Presentation: Sunday, July 13, 2025