ObjectiveEvaluate safety of Ovaprene, an investigational non-hormonal vaginal contraceptive designed for monthly use.Study designOpen-label, multicenter study enrolling heterosexually-active women with previous permanent contraception who underwent assessments during five menstrual cycles: baseline postcoital test cycle, diaphragm postcoital test cycle, Ovaprene safety cycle, and two Ovaprene postcoital test cycles. Safety outcomes included treatment emergent adverse events (TEAEs), systemic laboratory findings, pelvic examinations, colposcopies, Nugent scores, determination of community state types of vaginal microbiota, and anti-Escherichia coli activity and inflammatory markers in cervicovaginal fluids.ResultsWe enrolled 38 participants. Of these, 33 used Ovaprene and completed 77 Ovaprene cycles. The most common product-related urogenital TEAEs were bacterial vaginosis (BV) and vaginal odor. The frequency of transitioning from Lactobacillus-dominated community state type to community state type IV (not Lactobacillus-dominated) was similar before Ovaprene use and afterwards. Mean Nugent scores were <4 at each visit without a discernable upward trend. Inflammatory markers showed wide variation but no upward trend, and E. coli inhibitory activity of cervical secretions did not change. We found no Staphylococcus aureus, the causative agent in Toxic Shock Syndrome, on used Ovaprenes or in vaginal samples. No clinically important changes in systemic laboratory findings, pelvic examinations, or colposcopies occurred during Ovaprene use.ConclusionOvaprene use did not result in cervicovaginal irritation or adverse effects on resident vaginal microbiota, and did not impact transitions from a Lactobacillus-dominated community state type to community state type IV.ImplicationsThe finding that use of Ovaprene, an investigational monthly user-controlled nonhormonal vaginal contraceptive, does not appear to result in adverse changes in vaginal health during short term use supports further evaluation of the contraceptive potential of the device