One-third of gender-affirming testosterone users report breakthrough bleeding

Key takeaways:

• Overall, 34% of transgender and gender-diverse adults reported breakthrough bleeding while on testosterone.
• Breakthrough bleeding incidence was 0.09 per year in this population.

One-third of transgender and gender-diverse individuals on testosterone will experience at least one breakthrough bleeding episode, even after their first year of use, researchers reported in the American Journal of Obstetrics and Gynecology.

“We know that the majority of people who take testosterone gender-affirming hormone therapy will stop having periods within the first year. However, our study found that roughly one-third will eventually experience some degree of breakthrough bleeding, which can be anything from light spotting to something that feels more like a period,” Frances W. Grimstad, MD, MS, director of the Transgender Reproductive Health Program in the division of gynecology and the department of surgery at Boston Children’s Hospital and assistant professor of obstetrics, gynecology and reproductive biology at Harvard Medical School, told Healio. “Half of those who experience breakthrough bleeding will do so by the second or third year of testosterone use. While some people experienced breakthrough bleeding associated with missing a testosterone dose or taking one late, others experienced bleeding without any issues taking their medication.”

Grimstad and colleagues conducted a single-center, retrospective chart review with data from 279 transgender and gender-diverse individuals who were prescribed testosterone for at least 1 year. Researchers evaluated breakthrough bleeding incidence and assessed factors linked to bleeding in this population.

The median age at testosterone initiation was 22 years, and the median follow-up period was 34 months.

Frances W. Grimstad

Thirty-four percent of transgender and gender-diverse individuals included in the analysis experienced breakthrough bleeding while on testosterone. Those who experienced breakthrough bleeding had initiated testosterone therapy at a younger age (20.5 vs. 22 years; P = .04), had lower mean serum testosterone levels (389.14 vs. 512.7 ng/dL; P = .001), had a mean testosterone level less than 320 ng/dL (52% vs. 48%; P = .001) and had higher mean estradiol levels (62% vs. 49%; P = .003) compared with those without breakthrough bleeding.

In survival analyses, researchers estimated an incidence of 0.09 per year for breakthrough bleeding.

During the follow-up period, 58 individuals underwent hysterectomy. Of those who did not have a hysterectomy, 64% eventually experienced breakthrough bleeding. The median time to the initial breakthrough bleeding episode was 22 months following initiation of testosterone.

“More research [is needed] on whether different types of testosterone are associated with different frequencies of breakthrough bleeding, and what the best strategies are for managing breakthrough bleeding,” Grimstad said.

For more information:

Frances W. Grimstad, MD, MS, can be reached at frances.grimstad@childrens.harvard.edu.