Extended regimens of the combined contraceptive vaginal ring containing etonogestrel and ethinyl estradiol: effects on lipid metabolism.

BACKGROUND

Oral contraceptives used for extended periods of time have been studied because of their potential benefits; however, there have been few publications on extended regimens of vaginal contraceptive rings. The aim of this study was to evaluate modifications in the lipid profile of women using the vaginal ring continuously over a 1-year period.

STUDY DESIGN

This prospective cohort enrolled 75 women (18-37 years) who used a contraceptive vaginal ring releasing 120 mcg of etonogestrel and 15 mcg of ethinyl estradiol daily continuously for 84 days, followed by a 7-day ring-free interval, during 1 year. At baseline and every 3 months during the 1-year study period, blood was collected to assess cholesterol, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), triglycerides and apolipoproteins A-I and B. The ANOVA test was used to analyze differences in the results of these exams over time.

RESULTS

After 1 year of continuous contraceptive use, there was a significant increase in triglycerides as well as in total and HDL-C levels. There was a nonsignificant decrease in the mean concentration of LDL-C during the study period. Apolipoprotein A-I increased and apolipoprotein B decreased, but the apolipoprotein A-I/apolipoprotein B ratio did not change significantly.

CONCLUSION

The combined contraceptive vaginal ring used on an extended regimen causes changes in the lipid profile metabolism of users. Despite the vaginal route of administration, the steroids released by the ring caused significant changes in lipids and lipoproteins, which were typical of those seen with ethinyl estradiol given either orally or parenterally.