Effects of extended regimens of the contraceptive vaginal ring on carbohydrate metabolism

BackgroundThere are few publications on the metabolic effects of extended regimens of the contraceptive vaginal ring. The aim of this study was to assess changes in fasting plasma glucose levels and insulin concentration of women using the contraceptive vaginal ring continuously over a 1-year period.Study DesignThis prospective cohort enrolled 75 women (ages 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. Fasting glucose and insulin levels were measured, and homeostatic model assessment was calculated at baseline and every 3 months during the 1-year study period. The repeated-measures analysis of variance test was used to analyze differences in the results of these exams over time.ResultsNone of the 75 participants had results outside the normal range in any of the assessments. There were no pregnancies during the 1-year period, and a total of 62 participants completed the study. There were no significant changes in mean fasting glucose levels (79.3 and 78.9 mg/dL at baseline and after 12 months, respectively), mean fasting insulin concentration (9.6 and 10.1 μU/mL) or mean homeostatic model assessment results (1.88% and 1.97%).ConclusionFasting plasma glucose concentration, insulin levels and homeostatic model assessment values of women using the vaginal ring on an extended regimen did not change significantly over a 1-year period.