Background: Chronic pelvic pain (CPP) is a complex pain syndrome. Since its pathogenesis is still
poorly understood and structural alterations in pain related brain regions may be present, there is
a greater acceptance that sensitization of the central nervous system (CNS) plays an important role
in the development and maintenance of chronicity.
Objective: The purpose of this study is to systematically review the scientific evidence regarding
central sensitization (CS) in female patients with urogynecological CPP.
Study Design: Systematic review of the literature.
Methods: A systematic literature search was conducted in PubMed and Web of Science using
different keyword combinations related to urogynecological CPP and central sensitization. Full
text clinical reports addressing CS in adult women with urogynecological CPP were included and
assessed for methodological quality by 2 independent reviewers.
Results: After screening for the eligibility, a total of 29 full-text articles with low to good
methodological quality were retained. All studies were observational, 27 of which were casecontrol and 2 of which were cohorts. Sensitivity of the CNS was investigated by using a variety
of methods. Although different central mechanisms seem to be involved in pain processing, the
present evidence suggests hyperexcitability of the CNS in patients with urogynecological CPP.
Altered brain morphology and function, generalized hyperalgesia to different type of stimuli,
overactive bottom-up nociceptive mechanisms, and autonomic dysregulation were established
in patients with urogynecological CPP. Nevertheless, diffuse noxious inhibitory control seemed
normal, and therefore the contribution of an impaired endogenous pain inhibition mechanism to
CPP requires further study. The same goes for the contribution of psychological factors.
Limitations: The level of evidence of retained studies is low due to the observational study
designs and a wide range of diagnoses and assessment methods.
Conclusion: Although the majority of the literature provides evidence for the presence of CS in
urogynecological CPP with changes in brain morphology/function and sensory function, it is unclear
whether these changes in central pain processing are secondary or primary to CPP, especially since
evidence regarding the function of endogenous pain inhibition and the role of psychosocial pain
facilitation is scarce. Further studies with good methodological quality are needed in order to clarify
exact mechanisms.
Key words: Urogynecological pain, pelvic pain, chronic pelvic pain, hyperalgesia, sensitization,
central sensitization, pain processing, pain modulation, pain inhibition, systematic review