Single Arm Trial of Menstrual Cups Among Economically Vulnerable Women to Reduce Bacterial Vaginosis and STIs

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.