Levels of prolactin, a hormone associated with milk production, did not rise in a retrospective chart review of nearly 100 transgender (male to female) patients receiving feminizing hormone therapy, alleviating concerns about a possible side effect, a Mount Sinai researcher has found.
Estrogen, part of the standard feminizing hormone therapy regimen, can stimulate prolactin levels, and medical guidelines recommend routinely checking prolactin levels in transgender patients receiving hormone therapy. Although the over production of prolactin isn’t life-threatening, it can impair vision and produce other side effects.
The study is the first to measure prolactin levels in transgender patients receiving the standard feminizing hormone therapy regimen that is used in the United States and is significant because it demonstrates that gender-affirming treatment for transgender people may be safer than recognized.
Results of the study were published in Endocrine Practice, the journal of the American Association of Clinical Endocrinologists.
Researchers examined estrogen, testosterone, and prolactin levels from 98 transgender women treated with estrogen therapy at the Endocrinology Clinic at Boston Medical Center. Up to six years of data were available for some patients. The researchers found no elevated levels of prolactin in any of the patients.
“Our data suggests that there may be no significant rise in prolactin when transgender women are treated with estrogen and that it may be unnecessary to monitor prolactin in patients receiving this treatment,” said the study’s lead author, Joshua Safer, MD, executive director, Center for Transgender Medicine and Surgery at Mount Sinai.
Safer says that this study adds to the slim body of evidence-based literature in transgender medicine.
“Significant knowledge gaps exist across all of the subspecialties in transgender medicine and there is a lack of prospective robust research and representation of transgender-specific data in the core medical journals,” said Safer. “Studies like this improve our knowledge of the best ways to treat this population.”