HIV remains a global pandemic with 37 million infected. In western Kenya, 16% of women in the general population and 29% of the poorest women have HIV. The HIV and sexually transmitted infection (STI) epidemics overlap with broader reproductive health concerns. Menstrual hygiene management is a big problem in low- and middle-income countries and a lack of menstrual products negatively impacts women's work-life. This comes from cultural taboos, stigma, and discrimination, promoting secrecy around menstruation, high cost of menstrual products, use of traditional materials (e.g. rags, cotton wool, etc.) causing leakage and odor, and lack of water and safe hygiene facilities. Menstrual cups designed for use during sex may help women prevent Bacterial vaginosis (BV) and STIs through hygienic period practices, and may help them avoid bad practices in an attempt to maintain vaginal dryness. The goal of this interventional trial is to test the impact of menstrual cups on vaginal microbiome, BV, and STIs of poor women at high risk for STIs and HIV. We predict to see 25% less BV, our primary outcome, over one year. This trial aims to learn more about the safety of the intervention, and understand what is needed to fully implement the program.

In western Kenya, HIV prevalence is 16% among women in the general population, and 29% among the most economically constrained women. The HIV/STI epidemic overlaps with broader reproductive health concerns. Menstrual hygiene management (MHM) is a pervasive problem across low- and middle-income countries. In Phillips-Howards' survey of over 3,400 women in rural Kenya, two-thirds of women in impoverished settings state they depend on their sexual partners to provide branded products. Economically vulnerable women at high risk for HIV and STI are uniquely challenged because many continue to have sex during menses, and engage in harmful MHM practices, such as vaginal insertion of sponges and cotton to maintain dryness. Led by co-investigator Phillips-Howard, a cluster-randomized study of 644 girls aged 14-16 years old in western Kenya compared reusable menstrual cups to usual menstrual practice and counseling; after 9 months, menstrual cup use resulted in 35% reduction (p=0.034) in Bacterial vaginosis (BV) prevalence and 56% reduction (p=0.001) in STI prevalence compared to other materials. Among 431 Kenyan secondary schoolgirls aged 14-21, we observed cloth use for menses was associated with a 1.72-fold increased odds of non-optimal vaginal microbiome (CST-IV vs. CST-I: aOR=1.90; 95% CI: 1.03-2.86). Over 18 months of observation prior to COVID-19, girls using menstrual cups to manage menses had 20% higher occurrence of Lactobacillus crispatus dominated CST-I (aRR=1.29; 95% CI: 1.08-1.53, controlling for age, and baseline STI and sexual activity). Menstrual cups designed for use during intercourse may help women prevent BV and STIs through hygienic menstrual practices and avoidance of harmful practices to maintain vaginal dryness during menses. Objective: This single-arm interventional trial seeks to evaluate the preliminary efficacy of menstrual cups on non-optimal vaginal microbiome (VMB), BV, and STIs of economically vulnerable women at high risk for STIs and HIV, assess safety profile, and understand implementation needs. In Aim 1, we will evaluate the impact of menstrual cups on VMB, BV, and STIs among 402 economically vulnerable women in semi-urban Kenya. In Aim 2, we will conduct integrated surveillance for enhanced detection of safety endpoints, risk of cup contamination, and mitigating or facilitating water, sanitation, hygiene (WASH) factors. In Aim 3, we will identify constructs for successful MHM program implementation using an implementation science framework. Future Directions: The biological protection suggested in a randomized setting, and our findings that unhygienic cloth use is associated with non-optimal VMB, while menstrual cup use increases optimal VMB composition, together provide rational justification for this trial, of relevance to economically challenged women globally. Assessing preliminary efficacy signal in conjunction with implementation characteristics and adverse events, will generate a comprehensive and necessary foundation for definitive assessment of effectiveness of menstrual cups as a multipurpose intervention for MHM, and to reduce BV and STIs.

Inclusion Criteria:

• age 15-35 years,
• able to provide informed consent,
• residing in Kisumu County,
• not currently pregnant,
• has experienced a menstrual period in the past 2 months, and
• dependent on sex for livelihood as defined above.

Exclusion Criteria:

• pregnancy,
• post-natal (within 6 months),
• post-menopausal,
• amenorrhea,
• IUD in situ.

The interventional portion of this study includes only cis-gendered females, as outcomes related to the vaginal microbiome and menstruation are relevant only to biological females. To illustrate how menstrual hygiene management may biologically mediate the vaginal microbiome and subsequent related outcomes of BV and STIs, it is essential to enroll females.

Minimum IPD for main analysis replication will be made available at the time of publication. After completion of the study, data will be deposited in a registry for clinical trials data within 15 months.

ICFs and analytic code, will be included as supplementary material with published with manuscripts.