title: WHO systematic review of prevalence of chronic pelvic pain: a neglected reproductive health morbidity.
abstract: BACKGROUND
  Health care planning for chronic pelvic pain (CPP), an important cause of morbidity amongst women is hampered due to lack of clear collated summaries of its basic epidemiological data. We systematically reviewed worldwide literature on the prevalence of different types of CPP to assess the geographical distribution of data, and to explore sources of variation in its estimates.
  
  
  METHODS
  We identified data available from Medline (1966 to 2004), Embase (1980 to 2004), PsycINFO (1887 to 2003), LILACS (1982 to 2004), Science Citation index, CINAHL (January 1980 to 2004) and hand searching of reference lists. Two reviewers extracted data independently, using a piloted form, on participants' characteristics, study quality and rates of CPP. We considered a study to be of high quality (valid) if had at least three of the following features: prospective design, validated measurement tool, adequate sampling method, sample size estimation and response rate >80%. We performed both univariate and multivariate meta-regression analysis to explore heterogeneity of results across studies.
  
  
  RESULTS
  There were 178 studies (459975 participants) in 148 articles. Of these, 106 studies were (124259 participants) on dysmenorrhoea, 54 (35973 participants) on dyspareunia and 18 (301756 participants) on noncyclical pain. There were only 19/95 (20%) less developed and 1/45 (2.2%) least developed countries with relevant data in contrast to 22/43 (51.2%) developed countries. Meta-regression analysis showed that rates of pain varied according to study quality features. There were 40 (22.5%) high quality studies with representative samples. Amongst them, the rate of dysmenorrhoea was 16.8 to 81%, that of dyspareunia was 8 to 21.8%, and that for noncyclical pain was 2.1 to 24%.
  
  
  CONCLUSIONS
  There were few valid population based estimates of disease burden due to CPP from less developed countries. The variation in rates of CPP worldwide was due to variable study quality. Where valid data were available, a high disease burden of all types of pelvic pain was found.
authors.affiliation: Birmingham Women's Healthcare NHS Trust, Birmingham, UK. pallavi.latthe@bwhct.nhs.uk
authors.forename: Pallavi
authors.initials: P
authors.lastname: Latthe
authors.forename: Manish
authors.initials: M
authors.lastname: Latthe
authors.forename: Lale
authors.initials: L
authors.lastname: Say
authors.forename: Metin
authors.initials: M
authors.lastname: Gülmezoglu
authors.forename: Khalid S
authors.initials: KS
authors.lastname: Khan
mesh_terms: D002908:Chronic Disease; D019049:Developed Countries; D003906:Developing Countries; D004412:Dysmenorrhea / Q000453:epidemiology* / Q000503:physiopathology; D004414:Dyspareunia / Q000453:epidemiology* / Q000503:physiopathology; D016021:Epidemiologic Studies; D005260:Female; D014943:Global Health; D006801:Humans; D000292:Pelvic Inflammatory Disease / Q000453:epidemiology / Q000503:physiopathology; D017699:Pelvic Pain / Q000453:epidemiology* / Q000209:etiology; D015995:Prevalence; D012044:Regression Analysis; D018456:Reproductive Medicine; D014944:World Health Organization