Ohnut vs waitlist control for the self-management of endometriosis-associated deep dyspareunia: a pilot randomized controlled trial.

Background: Deep dyspareunia affects 50% of people with endometriosis. The Ohnut is a set of interlocking rings that fit over the penis/insertive object. One or more rings can be used to limit insertion depth and reduce deep dyspareunia.

Aim: We conducted a pilot, parallel, open-label randomized controlled trial (RCT) to investigate the feasibility of the study design and the acceptability and preliminary efficacy of the Ohnut.

Method: Participants were recruited from a tertiary center for endometriosis. Eligibility criteria were surgically confirmed endometriosis, age 19-49 years, monogamous sexual relationship with a partner willing to participate in the study, and no comorbid superficial dyspareunia, anxiety, or depression. Couples were randomized into an intervention group or a waitlist control group using a 1:1 allocation ratio. All couples had sex as normal during weeks 1 to 4 (baseline period), and couples in the intervention group used the Ohnut with sex during weeks 5 to 10 (intervention period) while controls had sex as normal. Patient participants used daily diaries to record sexual activity and deep dyspareunia score (0-10) for the 10-week study. Intervention group participants completed an acceptability questionnaire at the end of the study.

Outcomes: The primary outcomes were feasibility of the study and acceptability of the Ohnut. We also assessed differences in deep dyspareunia scores in the participants who used the Ohnut compared to the control participants who did not.

Results: We recruited approximately 5 couples per month of active recruitment. Of 864 potentially eligible participants, we successfully contacted 44.7% (n = 386), of whom 8.0% (n = 31) consented, 64.8% (n = 250) were ineligible, and 27.2% (n = 105) declined. Thirty-one couples were randomly assigned to the intervention or control group, and 17 couples completed the study. Intervention group couples used the Ohnut for an average of 72.4% (32.7%) of sexual encounters during the intervention period. The mean acceptability index score for the Ohnut was 0.83 (0.078) among patients and 0.83 (0.049) among partners (index between 0 and 1). After controlling for baseline deep dyspareunia, there was a significant difference in the intervention period mean deep dyspareunia scores between the control and intervention group (4.69 (2.44) vs 2.46 (1.82), P = .012).

Clinical implications: We identified preliminary evidence for the acceptability and efficacy of the Ohnut among both patients and partners, suggesting that the Ohnut may be a useful stand-alone or adjuvant management tool for endometriosis-associated deep dyspareunia.

Strengths and limitations: Strengths of this study were the "real-world" use of the Ohnut and data collection from both patients and partners. Limitations of the study design included the strict eligibility criteria that affected feasibility and generalizability.

Conclusion: This pilot RCT indicated that the Ohnut may be an acceptable and effective intervention to reduce endometriosis-associated deep dyspareunia. We identified opportunities to improve design for a larger RCT.

Clinical trial registration: This clinical trial was registered with clinicaltrials.gov (#NCT04370444).