Evaluation of the Effect of Water-Based Lubricants on the Vaginal Microbiome of Premenopausal and Postmenopausal Women [ID: 1376703]

INTRODUCTION: Over-the-counter personal lubricants are available to relieve intimate discomfort associated with vaginal dryness. However, little is known about how personal lubricants may affect the vulvovaginal microbiome. METHODS: The present study recruited 50 premenopausal and postmenopausal women with mild-to-moderate vaginal dryness and dyspareunia. Participants were randomized to one of five lubricant treatment groups (of ranging osmolality and pH), stratified to account for menopausal status, and instructed to use their assigned lubricant during vaginal intercourse at least once a week over a 4-week period. A total of four vaginal swabs were sampled per participant pre (“baseline”)- and post (“2 hours,” “24 hours,” and “4 weeks”)-lubricant application to assess bacterial and fungal microbiome diversity via 16S (V3-V4) and ITS1 rRNA sequencing, respectively. The 301x2 paired-end reads were preprocessed to remove nonbiological and poor-quality reads using the dada2 package in RStudio. Cleaned reads were converted into Amplicon Sequence Variants (ASV) and classified using the SILVA rRNA gene database for bacteria, and the UNITE database for fungi. ASV counts were normalized to relative abundance as a function of total number of ASV per sample. RESULTS: Nonparametric ordination methods and multivariate analysis of variance showed that repeated application of all lubricants tested, did not significantly alter the vaginal microbiome for up to 4 weeks after product application. Microbiome diversity and relative abundance differed significantly between premenopausal and postmenopausal women but remained unchanged before and after lubricant application. CONCLUSION: Overall, lubricant use was associated with maintenance of the vaginal microbiome, regardless of the participant's menopausal status.