Background: Intravaginal rings (IVRs) are being developed as multipurpose prevention technologies (MPTs) for simultaneous HIV and pregnancy prevention. However, no empirical data exists to support the current 54-58mm size as ideal. Understanding the impact of IVR size on adherence is critical for developing a product that can be used correctly and consistently. Methods: We conducted a randomized, open-label, 3-way crossover trial comparing adherence, preference, and acceptability of 3 non-medicated silicone IVRs of differing external diameters: 46mm, 56mm and 66mm. 24 couples in Atlanta, GA and Bronx, NY were randomized to the sequence of IVR use, used each continuously for ~30 days. The primary objective was to compare ring adherence, defined as never having the IVR out of the vagina for > 30 minutes in 24h. Women reported occurrence and duration of expulsions and removals via daily text. We summarized the proportion of days the IVR was removed, expelled, or out all day, and the proportion of women adherent to each IVR. We used mixed methods logistic regression models with random intercepts (per participant) to compare the probability of each event happening per day of IVR use, per IVR. Results: 23/24 couples completed the study. 78%, 75% and 59% of participants were adherent to the IVRs of diameter 46mm, 56mm and 66mm respectively (Table 1). The 46mm and 66mm IVR performed similarly, with more expulsions and 24h outages for the 66mm IVR. When adjusting for size and sequence, women had > 15 times the odds of the 66mm IVR being out all day versus the 56mm IVR (15.7, 95% CI: 3.4, 72.6). Conclusions: External diameter of these non-medicated IVRs had a significant impact on frequency of removal and expulsion. Product developers should prioritize IVRs in the range of 46mm-56mm.
Bruce, Irene, Marlena Gehret Plagianos, Jessica M. Sales, Jessica Atrio, Shakti Shetty, Caio Sant’Anna Marinho, Brady Zieman, Lisa Haddad, and Barbara Friedland. 2023. "Does size matter? A randomized controlled trial to assess the impact of external diameter on adherence to 3 different intravaginal rings among 24 US couples," presentation at the Adherence 2023 conference.
Intravaginal Ring Containing Etonogestrel, Ethinyl Estradiol, and QGriffithsin (EEQ IVR) to Prevent Pregnancy and HIV