PROLACTIN LEVELS DO NOT RISE AMONG TRANSGENDER WOMEN TREATED WITH ESTRADIOL AND SPIRONOLACTONE.

OBJECTIVE: Existing transgender treatment guidelines suggest that there is a need to monitor prolactin levels in patients receiving transfeminine hormone treatment. Also, recent studies suggest that use of cyproterone acetate as an adjunctive anti-androgen during transgender hormone treatment may elevate serum prolactin. We sought to determine whether the reported relationship between transfeminine estradiol treatment and hyperprolactinemia would be evident when the regimen used spironolactone as the adjunctive anti-androgen. METHODS: Estradiol levels, testosterone levels, prolactin levels, body mass index (BMI), and prescribed spironolactone dosage were extracted from the electronic medical records of 98 de-identified transgender women treated with estrogen therapy at the Endocrinology Clinic at Boston Medical Center (BMC). Up to 6 years of data were available for some patients. RESULTS: We found no statistically significant relationship between prolactin and any of the other measures. No estrogen dose-associated elevations in prolactin were found. None of the patients were diagnosed with prolactinoma. CONCLUSION: Our data suggest that there may be no significant rise in prolactin when transgender women are treated with estrogen along with spironolactone as the adjunct anti-androgen. It may be unnecessary to monitor prolactin in patients on this treatment combination. ABBREVIATIONS: BMI = body mass index; BMC = Boston Medical Center; HT = hormone therapy.