Secondary Vulvodynia Patients Show Reduced Bacterial Diversity in Vestibular Microbiome

Introduction: Localized Provoked Vulvodynia (LPV) is a quite common form of sexual pain among young women. Primary LPV (e.g. pain from the first attempted intercourse) and secondary LPV (pain-free time period before the initiation of symptoms) have been suggested to develop via different pathomechanisms. As inflammation is one possible trigger in LPV, changes in vaginal and/or vulvar microbiome may be an initiator of the inflammatory process leading to peripheral neurosensitization and predisposing women to LPV. Aim: Aim of this pilot study was to find out, whether there are differences in vestibular microbiome between LPV patients and controls. Materials and Methods: Thirty women with LPV (8 with primary and 22 with secondary LPV) and 21 controls were prospectively recruited to the study from Kanta-Hame Central Hospital and Tampere University Hospital (TAUH). Paired vestibular samples were collected in clinical outpatient setting and analyzed with 16s rRNA sequencing. Results: LPV patients had lower BMI, were younger and more often nulliparous than controls. Patients with secondary vulvodynia had reduced (p = 0.06) bacterial species diversity (alpha diversity) and more clustered (p= 0.05) vaginal microbiome community (beta diversity) compared to healthy controls. Differential abundance analysis identified 31 bacterial taxa that contributed to the difference in bacterial composition between secondary cases and controls (p