Objective: To compare the assessment of pelvic organ prolapse (POP) between the Pelvic Organ Prolapse Quantification (POP-Q) system with Valsalva maneuver and intraoperative measurement with mechanical traction.Methods: A prospective observational study included 100 women with POP attending a tertiary urogynecology clinic in the UK and undergoing vaginal prolapse surgical procedures between October 2011 and October 2014. The women were examined in the clinic using POP-Q with the Valsalva maneuver and in the operating theater under general anesthesia with mechanical traction. The two sets of measurements were compared.Results: All POP-Q measurements obtained with traction demonstrated significantly higher descent as compared with those measured by Valsalva maneuver (mean differences: Aa 0.64 cm; Ap 1.32 cm; Ba 0.96 cm; Bp 1.34 cm; C 3.57 cm; D 3.40 cm; all P<0.001). The perineal body and total vaginal lengths did not differ significantly.Conclusion: Measurements of six POP-Q points obtained with traction showed a higher grade of POP than those assessed with Valsalva maneuver. On this basis, surgeons might decide on the extent of surgical procedure after examination under anesthesia; however, preoperative patient counselling would be essential to obtain consent for this approach. The clinical significance of the findings requires further evaluation. [ABSTRACT FROM AUTHOR]