Provoked vestibulodynia : evaluation of a treatment modality and early life health

Abstract

Background: Provoked vestibulodynia (PVD) is a common cause of dyspareunia and have severe negative impact on the quality of life and sexual health in those afflicted. PVD can affect women at a young age without a clear cause and a theory is that birth-related events could contribute to the development of this condition. One important clinical finding is increased tension of the pelvic floor muscles (PFM). Various physiotherapeutic interventions are recommended as first line treatment, but these are not always effective and more options are needed.

Objective: The main aim of this thesis was to evaluate the effect of BTA-injections in the bulbocavernosus muscles as a treatment for PVD. Another aim was to investigate if birthrelated events could be a contributing factor to the etiology of PVD.

Material and Methods: We conducted a randomized controlled trial (RCT) were we evaluated the effect of bilateral injections of 50 U BTA in the bulbocavernosus muscles in women diagnosed with PVD, compared with placebo. Injections were given twice with three months’ interval. Forty-four women were randomized to BTA and 44 to placebo (in total 88 women). Our primary outcome measure was reduction in dyspareunia or pain at tampon use during the last month. Secondary outcomes were reduction in vaginal pressure as a measure of PFM function, pain at weekly tampon insertion, adverse events and sexual function and distress six months after the first treatment (Study I). A long-term follow-up of the RCT with additional pelvic floor exercises and psychometric evaluation, was conducted at 12 months (Study IV). In an effort to objectively investigate the PFM function in women with PVD, we evaluated a vaginal manometer measuring various vaginal pressures as a proxy for muscle function in women with PVD (n=60), nulliparous women (n=34) and primiparous women (n=34) (Study III). In Study II we conducted a register study were all women born in Sweden between 1973 and 2001 were categorized into those with and without a PVD/vaginismus diagnosis between 2001 and 2016. Here we estimated the association between health during infancy and onset of PVD/vaginismus later in life.

Results: In Study I and IV twice repeated injections of 50 U BTA in women with PVD did not reduce dyspareunia or pain at tampon use. Secondary results showed a significant decrease in pain at weekly tampon insertion. The vaginal manometer detected a transient lower maximum contraction and 10-second endurance contraction in the BTA group compared with the placebo group during the time period when the drug was active. No severe adverse events were reported. The group receiving BTA also had an increased number of intercourse attempts compared with placebo at both 6- and 12-months’ follow-up. In study III, all pressure variables showed a similar pattern when comparing the groups. The vaginal resting pressure was lower in primiparous women compared to nulliparous women but not the PVD group. The maximum contraction and endurance pressure was similar for PVD and nulliparous women. Primiparous women exhibited lower pressure in both these variables compared with the other groups. Intra-rater reliability for the VRP variable was moderate and good to excellent intra-rater reliability for MCP and EP. The inter-rater reliability showed excellent reliability for all variables. In Study II adverse health at birth, such as preterm delivery, low birth weight and small for gestational age was found to be associated with developing PVD/vaginismus later in life. In contrast to our hypothesis, we found no evidence to suggest that pain exposure early in life is positively associated with developing PVD/vaginismus later on in life.

Conclusions: BTA does have a detectable muscular effect on women with PVD, but the effect on dyspareunia and the optimal dose to reduce this still remains to be determined. After 12 months, increased sexual function and significant increase in number of intercourse attempts were observed in the BTA group. The vaginal manometer was deemed a functional tool to detect differences in vaginal pressures during different states of PFM activity and varying parity with good intra- and inter-rater reliability. Adverse events at birth such preterm delivery, SGA and low birth weight could be contributing factors for developing PVD/vaginismus later in life.