Improving menstrual and vaginal health for all (IMVAHA): protocol for a randomised cross-over trial assessing the impact of menstrual products on the vaginal microbiome of women aged 18-35 years in Cameroon, Peru and Switzerland

Introduction Menstrual health is critical to achieving gender equity and reaching the 2030 Sustainable Development Goals, yet evidence on the health impacts of menstrual products - particularly on the vaginal microbiota - is limited. The Improving Menstrual and Vaginal Health for All (IMVAHA) project aims to address this knowledge gap through qualitative exploration, a health survey and clinical trial embedded in three sister projects: Laura (Peru), Leke (Cameroon) and Marie (Switzerland).

This paper outlines the protocol for the IMVAHA health survey and clinical trial studies, which aim to (1) assess menstrual hygiene practices, product preferences and vaginal health; and (2) evaluate longitudinal changes in vaginal microbiota associated with the use of pads, tampons and menstrual cups. Methods and analysis The IMVAHA project will take place in urban Cameroon, urban Peru, and in Switzerland.

The baseline survey will explore vaginal and menstrual health behaviours and preferences, including vaginal complaints, menstrual products and menstrual stigma.