Metabolic safety of the etonogestrel contraceptive implant in healthy women over a 3-year period

Objective: To ascertain whether placement of the etonogestrel contraceptive implant induces significant changes in carbohydrate and lipid metabolism, as reflected by metabolic parameters, in healthy women.

Study design: Prospective cohort study of 213 healthy patients who received etonogestrel implants. Weight, BMI, blood pressure and a comprehensive metabolic profile were assessed at baseline, 1, 2 and 3 years. In 21 of the 213 participants, AUC for glucose levels, fasting insulin levels at baseline and year 3 (immediately before implant removal), HOMA-IR score, and the QUICK index were assessed. Parameters were expressed as median and interquartile range. The Wilcoxon test and ANOVA were used for comparison of measurements after implant placement (significance level p<0.05).

Results: Median age was 26 years (range, 22-31.5). Results showed a trend toward increase of the variables weight (63.3-66.1) and BMI (24.7-25.7) and a decrease in TC (172-161.5), TG (75-69.5), and LDL (100.5-98.5) (p>0.05). Of the metabolic variables, FBG (85-88) and HDL (53-46) had significant differences (p<0.002). In the subgroup of 21 patients, there were reductions in insulin levels (9.65 vs. 8.4mU/dL, p=0.03), HOMA scores (2.06 vs. 1.75, p=0.02), QUICK index (0.34 vs. 0.35, p=0.03), TC (178 vs. 160mg/dL, p=0.001), HDL (51 vs. 46mg/dL, p=0.009), and LDL (110 vs. 100mg/dL, p=0.035).

Conclusion: These results provide evidence of the metabolic safety of the ENG implant in healthy women over a 3-year period. Indeed, implant placement induces changes consistent with a lower risk of insulin resistance and dyslipidemia.