This project is funded by NIH to Dr. Surpiya Mehta (PI) at University of Illinois at Chicago with a sub-contract to NRHS. Among 440 schoolgirls aged 14-25 years, we will study the effects of menstrual cup use on the vaginal microbiome (VMB) and whether this leads to reduced BV and STIs, and how menstrual cup use effects the adolescent VMB over time. This study is nested within a cluster randomized controlled trial involving over 4,000 schoolgirls in Siaya County, Kenya.