by
Richard E. Haaland;
Angela Holder;
Tammy Evans-Strickfaden;
Beatrice Nyagol;
Mumbi Makanga;
Boaz Oyaro;
Felix Humwa;
Tiffany Williams;
Eleanor McLellan-Lemal;
Mitesh Desai;
Michael Huey
Objective:
This study sought to measure residual contraceptive hormone levels in vaginal rings as an adherence marker for monitoring product use in clinical trials.
Study design:
Residual etonogestrel and ethinyl estradiol levels from used NuvaRings® of 26 self-reported adherent women enrolled in a clinical trial of vaginal ring acceptability were compared to those from 16 women who used NuvaRing® as their contraceptive choice.
Results:
Twenty-one (81%) clinical trial rings had contraceptive hormone levels within the range of those used as a contraceptive choice. Five returned rings had unused or discordant levels of residual contraceptive hormones.
Conclusion:
Residual vaginal ring drug levels could help assess adherence in clinical trials.