Continuation Rates of the Etonogestrel Implant and Factors Associated With Early Discontinuation

Abstract

Background: The etonogestrel implant is generally considered an effective, three-year, long-acting reversible contraceptive device. Previous research, such as the landmark CHOICE study, has reported a one-year continuation rate of 72% to 84%, however, in a real-world setting these rates may be significantly lower.

Objective: To study etonogestrel implant continuation rates and factors associated with early discontinuation in a specific clinical setting.

Study design: Single-center, retrospective cohort study of patients who received the etonogestrel implant between January 1, 2015, and December 31, 2017, at several practices at an academic community hospital network. Records were reviewed up to three years after implant insertion to determine continuation rates (one to three years), early discontinuation rates (≤12 months), and reasons for early discontinuation. A sample size calculation was performed to guide a subanalysis of side effects.

Results: A total of 774 patients underwent etonogestrel insertion during the study period. The one-year continuation rate was lower than that of the CHOICE study (62% vs. 83%, P <0.001). A subanalysis (n=216) revealed that a majority (82%, n=177) of patients reported side effects. Side effects were more common in patients with early discontinuation compared with patients who continued use longer than one year (93% vs. 71%, P <0.001). The most common side effect, abnormal uterine bleeding, was not significantly associated with early discontinuation. A significant association (P=0.02) was found between early discontinuation and neurologic/psychiatric complaints.

Conclusions: The one-year continuation rate of the etonogestrel implant in our population is significantly lower than the value reported by CHOICE. Implant side effects are common and significantly affect rates of discontinuation. Our data suggest there is an opportunity for education and counseling for individuals opting for this method of long-acting contraception.

Keywords: abnormal uterine bleeding; contraception; etonogestrel implant; long-acting contraception; side effects; unplanned pregnancy.

Figure 1. Population selection and study design

Figure 2. Etonogestrel implant continuation rates over time