Amenorrhea in adolescents using the etonogestrel contraceptive implant

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.

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.

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.

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.

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.