Abstract
OBJECTIVE: Investigate the association between use of depot medroxyprogesterone acetate (DMPA) (an injectable progestin-only contraceptive) and leiomyoma development. METHODS: We conducted a cohort study in the Detroit, Michigan, area that involved four clinic visits at 20-month intervals over 5 years (2010-2018) and used a standardized ultrasonography protocol to prospectively measure leiomyomas 0.5 cm or more in diameter. Participants were 1,693 self-identified Black women aged 23-35 years with no prior leiomyoma diagnosis and no hysterectomy. For this substudy, years since last use of DMPA was ascertained from questionnaire data at every visit. Leiomyoma incidence was defined as the first visit with an observed leiomyoma among women who were leiomyoma-free at enrollment. Depot medroxyprogesterone acetate associations were examined with Cox models. Leiomyoma growth was calculated as the change in log-volume for leiomyomas matched at successive visits and was modeled using linear mixed models accounting for clustered data. Leiomyoma loss, defined as a reduction in leiomyoma number in successive visits, was modeled using Poisson regression. All models used time-varying exposure and covariates. RESULTS: Of participants with at least one follow-up visit (N=1,610), 42.9% had ever used DMPA. Participants exposed to DMPA within the previous 2 years experienced reduced leiomyoma development during the subsequent observation interval compared with never users, including lower leiomyoma incidence (5.2% vs 10.7%), adjusted hazard ratio 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 for those who used DMPA 2-4 years before the visit compared with never users, 2.1-fold increase (95% CI 1.4-3.1). CONCLUSION: Recent use of DMPA was associated with reduced leiomyoma development and increased leiomyoma loss. Such changes in early leiomyoma development in young women could delay symptom onset and reduce the need for invasive treatment.