Objectives: The aim of the study was to assess the incidence of adverse effects (AE) reported with etonogestrel contraceptive implant in France (Implanon® and Nexplanon®).
Materials and methods: All cases of AE or unintended pregnancies reported to health authorities or to the firm were analyzed.
Results: During 10 years, 5433 AE and 789 unintended pregnancies were reported. Only 388 (7 %) were serious. There were 1137 reports of difficulties to remove, failure to locate or migration, 430 of insertion difficulties and 203 of deformation or expulsion of the implant. Among other AE, the most common were 1694 gynecological AE, 524 skin reactions and 437 metabolic AE. Since the marketing of Nexplanon® which causes less deep insertions, the incidence of migrations, removal or insertion difficulties has decreased overall (0.92 vs. 1.31/1000 patients), particularly the incidence of removal difficulties, location failures or migrations (0.12 vs 1.01/1000). The infrequent but serious AE were infectious complications at the implant site and pregnancies. When the circumstances of the pregnancy were known, the contraceptive failure was due to the apparent inefficiency of the implant (n=224), to a technique failure (n=203) or to a drug-drug interaction (n=59).
Conclusion: This study confirms that AE of this implant are frequent but not serious, except for the pregnancies. The incidence of complications related to insertion decreased with Nexplanon®. Among other preventable AE, unintended pregnancies due to a drug-drug interaction would require to be better known by the practitioner.
Keywords: Adverse effects; Effets indésirables; Etonogestrel; Implant; Étonogestrel.
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