Dyspareunia is rarely assessed in rodent models of endometriosis and interstitial cystitis/bladder pain syndrome.

Abstract: Dyspareunia, or pain during sex, is a common and often debilitating symptom in individuals with endometriosis and/or interstitial cystitis/bladder pain syndrome (IC/BPS). Despite its significant impact on quality of life, it is frequently overlooked in research. This review evaluates how dyspareunia has been addressed in preclinical investigations of these conditions. A systematic search was conducted using Embase from 1998 to 2021, identifying original in vivo preclinical studies using female rodents to model (i) endometriosis and (ii) IC/BPS. The search aimed to identify studies that assessed dyspareunia. Study quality and risk of bias were evaluated using a modified CAMARADES checklist. Our analysis found 1,286 studies modelling endometriosis and 674 modelling IC/BPS, but only 18 and 1, respectively, measured dyspareunia. The most common method involved vaginal distention in rats, assessed by either behavioural escape responses or visceromotor reflexes of abdominal muscles. Despite the high prevalence of dyspareunia in these conditions, it is rarely measured in preclinical studies. We identify a significant gap in the literature and offer succinct recommendations for future translational research to address this important symptom.

Lay summary: Dyspareunia describes pain occurring before, during or after sexual intercourse. This poorly understood symptom is particularly common in people suffering from two chronic pain-related conditions: endometriosis and IC/BPS, severely impacting their quality of life. Therefore, effective treatments addressing painful sex in people with these conditions are needed. To see the benefits of medical research at the patient's bedside, it is important to build from basic science research to preclinical animal studies then to human studies. Our study aims to assess the work that has been done so far at the 'preclinical' stage. Developments have been made in the methodology used to investigate this symptom in animals, and a summary of all the key findings may help build a platform to design future studies. Given the urgent need to develop new therapeutic strategies, attention given to painful sex by scientific medical researchers and physicians needs to improve.