An exploratory study on the association of lifestyle factors with serum etonogestrel concentrations among contraceptive implant users

PURPOSE: To explore how diet and exercise habits associate with serum etonogestrel concentrations among contraceptive implant users. MATERIALS AND METHODS: We conducted a secondary analysis of healthy, reproductive-age women using etonogestrel implants. This study was registered on ClinicalTrials.gov, NCT03092037. We assessed diet and exercise habits with two validated surveys: Healthy Eating Vital Signs and the Stanford Brief Activity Survey. Participants previously had their serum etonogestrel concentrations measured using a validated liquid-chromatography mass-spectrometry assay. We then used linear modeling to test for associations between survey responses and serum etonogestrel concentrations. RESULTS: Among 129 participants, diet and exercise habits had no significant associations with serum etonogestrel concentrations (p= 0.22–0.72), with inconsistent effects found for increased caloric intake and sedentary lifestyle. CONCLUSION: This exploratory study found no significant effect of diet or exercise habits on steady-state pharmacokinetics among contraceptive implant users.