Assessing for Ovulation in Transmasculine Individuals on Testosterone: Implications for Unmet Need for Contraception in the Trans Community

Abstract

Importance: An estimated 1.4 million people in the United States identify as transgender or non-binary (TNB), signifying that their gender identity does not correspond with their assigned birth sex. Individuals assigned female at birth may seek gender-affirming hormone therapy with injectable testosterone. No studies have directly examined ovulatory function or contraceptive need in transmasculine individuals on testosterone. Objective: Our objective was to determine whether testosterone reliably suppresses ovulation in transmasculine individuals, and to use this and existing data to perform an assessment of unmet need for contraception in this population. Methods: This is a observational prospective trial based at a community clinic serving over 400 patients annually for gender affirming hormone therapy. We enrolled individuals who were assigned female at birth and are currently using or seeking to initiate masculinizing therapy with testosterone (transmasculine individuals). Over a 12-week study period, subjects collected daily urine samples for pregnanediol-3-glucoronide (PdG) testing and completed daily electronic bleeding diaries. We collected monthly serum samples for mid-dosing interval serum testosterone, estradiol and sex-hormone binding globulin (SHBG) levels, and anti-mullerian hormone (AMH) values at baseline and study end. Ovulation was defined as PdG>5µg/mL for three consecutive days. We then used these data and the existing literature on fertility and family planning in this population to perform an assessment of unmet need for contraception. Main Outcomes and Measures: Our primary outcome was the proportion of participants who ovulated during the study period. Secondary outcomes included predictors of ovulation such as age, length of time on testosterone, serum testosterone levels, body mass infex (BMI), and bleeding pattern. Results: We enrolled 32 individuals and 20 completed the entire study. Median age was 23 (range 18-37). Six participants were new initiators of testosterone and 14 were continuing users. Among continuing users, median duration of testosterone therapy was 9 months (range 2-60 months). One participant-month of ovulation was observed using the standard criteria, however several other participants had transient rises in PdG followed by bleeding episodes suggestive of a dysfunctional ovulatory pattern. Significant research gaps exist in assessing for unmet need for contraception in the transmasculine population. Conclusions and Relevance: This study suggests that testosterone rapidly induces ovulatory dysfunction leading to eventual ovulatory suppression, though intermittent ovulations may be possible even in long-term users. Contraceptive need is largely unrecognized in this community, and more data are needed.