Amenorrhea in adolescents using the etonogestrel contraceptive implant

Objective: Clinical factors related to development of amenorrhea in adolescents with the etonogestrel contraceptive implant are not well-understood. The purpose of this study is to describe what baseline clinical characteristics are associated with amenorrhea in adolescents with a contraceptive implant 12 months after placement.

Study design: This retrospective cohort study included 252 post-menarchal individuals aged 12-22 years with a contraceptive implant placed between 2016-2020. Data abstracted at insertion, three months post-insertion, and 12 months post-insertion included demographics, baseline bleeding pattern, prior contraception use, post-insertion bleeding pattern, and method discontinuation. We assessed possible predictive characteristics of our outcomes using bivariate and multivariable logistic regression analyses.

Results: Twenty nine percent of patients were amenorrheic 12 months after placement. Patients who were amenorrheic at 12 months were more likely to be obese (41.1% vs 24.6%, p = 0.01), to have been amenorrheic prior to implant insertion (16.9% vs 5.4%, p < 0.01, to have used hormonal contraception immediately prior to insertion (42.5% vs 26.3%, p = 0.01), to have had the most recent contraceptive method being another implant (12.3% vs 3.6%, p = 0.02), and to have developed amenorrhea within three months after placement (22.2% vs 12.6%, p < 0.01). After multivariable regression analysis, only obesity (adjusted odds ratio [aOR] 2.2 95% CI 1.1-4.2) and amenorrhea at three months (aOR 3.6, CI 1.1-11.5) were associated with amenorrhea at 12 months.

Conclusion: Obesity and early amenorrhea were associated with 12-month amenorrhea in adolescents using the etonogestrel subdermal implant. Understanding this can help with contraceptive method selection and counseling for patients and providers.

Implications: Obesity and early amenorrhea with the etonogestrel contraceptive implant are associated with longer-term amenorrhea in adolescents using this method. These findings can aid providers with method selection and pre-insertion decision-making for adolescents considering contraceptive implant use, as well as continued counseling after placement.