Metabolic effects of contraceptive implants in adolescents.

Background: This prospective study analyzed the metabolic effects of an etonogestrel implant used for 1 year by adolescents.

Study Design: The study population comprised 47 postpartum adolescents (mean 17.2 years old) managed at the Family Planning Sector of São Paulo Federal University. Participants received an implant containing etonogestrel (68 mg) within 6 months of delivery (on average 102 days after giving birth) and were followed for 1 year. Blood was collected at baseline and 12 months later to assess total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), triglycerides (TG), hemogram, urea, creatinine, sodium, potassium, fasting glucose, serum glutamic oxaloacetic transaminase (SGOT), serum glutamic pyruvic transaminase (SGPT) and bilirubin.

Results: Three adolescents did not return after receiving the implant despite telephone messages and a telegram and were excluded from the clinical and final laboratory analyses. All 44 patients completed the 12 months of follow-up, resulting in a study discontinuation rate of 0%. No implants were removed. Laboratory analyses were completed in 37 adolescents. After 1 year of using the implant, there was a significant increase in mean hemoglobin, hematocrit and indirect bilirubin concentrations and of the HDL-C/TC and HDL-C/LDL-C ratios. Additionally, there was a significant decrease in mean TC level as well as LDL-C, very low-density lipoprotein cholesterol, TG, SGOT and SGPT. These results suggest that the etonogestrel implant does not interfere directly with the risk of cardiovascular diseases because it improves the lipid profile. There were no pregnancies during the study.

Conclusion: Our results indicate that an etonogestrel implant used by adolescents for 1 year is associated with changes in the lipid profile and hepatic function without adverse clinical effects.