1018 Stage 0 Stage 1 Stage 2A Stage 2B Stage 2C Stage 3 Stage 4 Table 2 The prevalence of POP stage in relation to the report of vaginal bulging in percentage (n); POP data were missing in six women; vaginal bulging question had not been answered by ten women) Vaginal bulging Symptomatic n=79 Asymptomatic n=570 15.6 (12) 20.8 (16) 18.1 (14) 16.9 (13) 7.8 (6) 16.9 (13) 3.9 (3) 26.3 (146) 39 (217) 17.8 (99) 10.1 (56) 3.7 (6) 3.1 (17) 0 in the numbers on the score chart, the total score can be interpreted on the prognostic curve and will give the risk for the presence of POP in percentages. A shrinkage factor of 0.63, estimated from the bootstrap validation procedure, was applied to this model to enable optimal predictive performance in new subjects. Discussion The present study was designed to investigate the preva- lence of POP in a general female population and to develop Int Urogynecol J (2009) 20:1013–1021 a prediction model based on prognostic factors that could be considered into a prognostic index. Prevalence The distribution of pelvic organ prolapse in this population indicated that POP was present at or beyond the hymen (≥stage 2B) in 21% of the women. Within this 21%, 45% of the women had reported the symptom of seeing and/or feeling vaginal bulging. If stage 2A had been included, the prevalence would have increased to 36.4%, which is in line with the study by Gutman et al. [18]. Our results are also comparable with those reported in many other studies, but as yet, no reliable explanation has been put forward for the discrepancy between POP stage and symptoms of vaginal bulging [3, 9, 19–21]. Explanations for the discrepancies between POP signs and POP symptoms might lie in the personal sphere, such as coping strategies, attitudes and beliefs, or in the social and economic circumstances, such as quality of life. We recommend that future research focuses on these personal and socio-economic factors in relation with POP. Another possible underlying factor in the lack of conformity between the report of the symptom of vaginal bulging with the signs of POP stage is the reliability of the POPQ measurement. Results can be influenced by the level of fullness of the bladder and bowel and by reluctance to make a maximum valsalva manoeuvre on command during Table 3 Results of the multivariate logistic regression analysis with test scores and area under the curve (AUC) in POP substages 2A, 2B and 2C in relation to the hymen (pregn. POP = vaginal bulging symptoms during pregnancy with at least a little bother) Distance ≥ −1, 2A Distance ≥ 0, 2B Distance ≥ 1, 2C Vaginal bulging Age (years) BMI Nulliparous 1 child 2 children ≥3 children Postmenopausal status Smoking current Inc surgery Educ level intermediate Heavy work current Heavy work past Pelvic girdle pain Pregn. POP Mother POP Significance level 0.30 OR 3.05 0.44 1.56 1.54 1.29 0.52 2.23 0.67 1.32 1.40 1.55 95% CI 5.13 0.17 0.90 0.85 0.86 0.33 0.92 0.39 0.85 0.95 0.99 1.81 1.17 2.69 2.78 1.94 0.82 5.41 1.14 2.04 2.07 2.42 OR 3.80 1.04 1.16 2.84 2.63 0.62 2.11 0.56 1.44 1.96 95% CI 6.53 1.01 0.31 1.28 1.13 0.35 0.83 0.92 0.89 1.22 2.22 1.06 4.30 6.30 6.11 1.09 5.37 2.66 2.33 3.15 OR 5.47 1.04 0.94 0 3.06 3.33 0.57 1.53 1.71 0.54 2.00 95% CI 10.45 1.01 0.87 0 0.97 1.00 0.25 0.71 0.88 0.19 1.00 2.97 1.08 1.02 >1,000 9.70 11.00 1.31 3.35 3.32 1.55 3.97