**3. Prevalence of pelvic organ prolapse associated stress urinary incontinence**

The exact prevalence of pelvic organ prolapse is difficult to estimate due to patient misunderstandings and misconceptions in presenting these issues to their health care providers. Most of the estimated prevalence rates for pelvic organ prolapse are derived from the incidence of surgery for this disease or from clinic-based samples (Lawreence et al., 2008). Pelvic organ prolapse has been estimated to affect about 50% of parous women aged 50 years or over whereas stress urinary incontinence occurs in 30%. These prevalence rates increase with age (Subak et al., 2001; Abou-Elela et al., 2009; Maher et al., 2010). Pelvic organ prolapse and stress urinary incontinence coexist in 15 to 80 percent of women (Bai et al., 2002). Experts estimate that up to 50% of women with pelvic organ prolapse with the uterus in situ do not have stress urinary incontinence (Gallentine and Cespedes, 2001).

This continence mechanism in advanced pelvic organ prolapse might be caused by urethral kinking or external urethral compression, which causes obstruction that can stop the demonstration of stress urinary incontinence (Romanzi et al. 2000; Elneil, 2009). However, during surgery to reduce the prolapsed uterus or anterior vaginal wall it may be noted from the urodynamic study that 36 to 80% of the women with pelvic organ prolapse have coexisting urodynamic stress incontinence. These patients have occult stress urinary incontinence (Haessler et al., 2005; Reena et al., 2007). In addition, postoperative stress urinary incontinence (de novo stress urinary incontinence) has been noted in 10 to 30% of women following prolapse repair (Bump et al., 1996; Hung et al., 2004; Reena et al., 2007). Other reports estimate that 11 to 65% of continent patients with pelvic organ prolapse develop de novo stress urinary incontinence following pelvic reconstructive procedures performed during prophylactic anti-incontinence surgery (Borstad E and Rud T, 1989; Ellerkmann et al., 2001; Gutman et al., 2008).
