(024) A Randomized Trial on the Sexual Effectiveness and Impact on the Vaginal Microbiome of Reformulated Personal Water Lubricants with Lowered Osmolality and pH in Premenopausal and Postmenopausal Women
Authors: Krychman M , Palacios S , Freixas-coutin J , Seo J 
Published: May 2023

Abstract

Introduction
Vaginal dryness may be associated with postmenopausal women; however, it may also occur due to chronic medical conditions and as a direct side effect from medications. Personal lubricants can address sexual complaints and symptomatology associated with vaginal dryness, although clinically published data supporting their efficacy remains limited. Age-associated vaginal-physiological changes due to hypoestrogenic milieux include increased pH, decreased natural lubrication, reduced endothelial rugae and altered vaginal microbiome. While personal lubricants may alleviate symptoms, their definitive effects on the vaginal microbiome remain understudied and underappreciated.

Objective
This study examined reformulated water-based lubricants (lowered osmolalities and pH,) and their effect on female sexual function compared to their counterparts (higher osmolalities/increased pH). A secondary analysis examined if these reformulated lubricants influenced the vaginal microbiome of women from different age groups.

Methods
An open-label, parallel-design study was performed in heterosexual women in stable monogamous relationships, aged 18–65 years with mild-to-moderate vaginal dryness and dyspareunia. The study population (n=174) included an approximate 50:50 ratio of premenopausal to postmenopausal women. The randomization schedule was stratified by menopausal status. Subjects were randomized to use one of five water-based lubricants and instructed to use their lubricant during vaginal intercourse at least once a week over a 4-week period. The Female Sexual Function Index (FSFI) measured sexual functioning after 4 weeks of use as an indicator of lubricant performance. More than a 4-point increase in total FSFI is deemed clinically important. From the study-enrolled subjects, 50 females were randomized to one of five lubricant treatment groups for secondary microbiome analysis. To this end, four vaginal swabs per participant were sampled during pre- (“baseline”) and post- (“2 hours”, “24 hours” and “4 weeks”) lubricant application to assess bacterial diversity via 16S sequencing. Additionally, vaginal moisture and pH measurements were collected at baseline, 2 hours, and 24 hours post-lubricant application and correlated with microbiome diversity and richness using non-parametric tests and linear mixed models.

Results
An increase in FSFI total score of &gt;4 points was found for all lubricants in the total population and for 4/5 lubricants in the premenopausal subgroup, as indicated by the mean differences to baseline. The number of subjects in sexual function (total FSFI &gt;26.55) after treatment was significantly greater than the number in sexual function before treatment for both subgroups (premenopausal 19.3% to 78.4%; postmenopausal 22.3% to 75.3%; p&lt;0.0001 for both). Lactobacillus species and Gardnerella vaginalis were the predominant taxa across all participants. Repeated lubricant applications did not alter the vaginal microbiome for up to 4 weeks post-product applications. Microbial diversity and relative abundance differed significantly between age groups but remained unaffected during product applications. Relative abundance of Lactobacilli spp. negatively correlated with vaginal pH while that of Gardnerella spp. showed a positive correlation with vaginal pH across all age groups.

Conclusions
These reformulated lubricants can be used not only to relieve symptomatology of vaginal dryness and dyspareunia, but to enhance overall sexual satisfaction regardless of menopausal status. These study lubricants demonstrated no significant impact on vaginal microbiome. Further studies with larger samples are warranted.

Disclosure
Yes, this is sponsored by industry/sponsor: Reckitt Benckiser Health.
Clarification: Industry funding only - investigator initiated and executed study.
Any of the authors act as a consultant, employee or shareholder of an industry for: Reckitt Benckiser Health.