For a study, researchers sought to examine the link between the usage of depot medroxyprogesterone acetate (DMPA), an injectable progestin-only contraceptive, and the development of leiomyoma. They conducted cohort research in the Detroit, Michigan, region that included four clinic visits at 20-month intervals over a 5-year period (2010–2018) and utilized a standardized ultrasonography methodology to assess leiomyomas 0.5 cm or larger in diameter. Participants were 1,693 self-identified Black women between the ages of 23 and 35 who had never had a hysterectomy or been diagnosed with leiomyoma. The years since the last usage of DMPA were determined from questionnaire answers at each visit for this substudy. The first visit with an observable leiomyoma among women who were leiomyoma-free at enrolment was used to calculate leiomyoma incidence. Cox models were used to look at depot medroxyprogesterone acetate relationships. Leiomyoma growth was estimated as the change in log volume for leiomyomas matched at subsequent visits and was analyzed using linear mixed models that took clustered data into consideration. Poisson regression was used to simulate leiomyoma loss, which was defined as a decrease in leiomyoma number over time. Time-varying exposure and variables were employed in all models.

About 42.9% of individuals with at least one follow-up visit (N=1,610) had ever taken DMPA. Participants who had been exposed to DMPA within the previous two years had lower leiomyoma incidence (5.2% vs 10.7%), the adjusted hazard ratio of 0.6 (95% CI 0.4–1.0), 42.0% lower leiomyoma growth (95% CI 51.4 to 30.7), and 60% greater leiomyoma loss (adjusted risk ratio 1.6, 95% CI 1.1–2.2). Excess leiomyoma loss was also seen in individuals who had taken DMPA 2–4 years before the visit compared to those who had never used it, a 2.1-fold increase (95% CI 1.4–3.1). Recent DMPA use was linked to decreased leiomyoma formation and enhanced leiomyoma loss. Such modifications in the early stages of leiomyoma formation in young women might postpone symptom onset and lessen the need for invasive therapy.