
Introduction: The subdermal implant is a highly effective family planning option. Identifying adverse effects allows us to understand the epidemiological behavior of this method. Objective: To determine the prevalence, time of onset, and duration of adverse effects of the etonogestrel subdermal implant. Materials and methods: A descriptive cross-sectional design was performed in 50 women who were users of etonogestrel subdermal implants. The types of adverse effects, their number, prevalence, time from onset to application, and duration of the effect from the time of implant application were identified. Results: The average age was 28.84 years (95% CI; 26.98–30.70). The most frequently occurring adverse effect was menstrual irregularities in 98.0% (95% CI: 93.9–100.0); the onset time was 3.31 months (95% CI' 1.40–5.21) after implant application, and the average duration was 35.76 months (95% CI; 26.97–44.54). In women with etonogestrel subdermal implants, 100% experienced one or more adverse effects. Conclusion: The prevalence of adverse effects from the use of etonogestrel subdermal implant is high, and several adverse effects occur at different times and durations.