**2. Incidence and epidemiology**

The incidence of asymptomatic prolapse is high, with approximately 50% of the women after vaginal delivery having an asymptomatic descensus in gynecological examination. 8–30% of the women report symptoms of pelvic floor disorders [1]. The most common symptom of pelvic floor disorders are symptoms related to urination with up to 40% of women suffering from urinary incontinence and bladder voiding dysfunction [2]. The prevalence of pelvic floor disorders rises with age, with 9.7% of the women aged between 20 and 39 years and 49.7% of the women at the age of 80 or older reporting at least one pelvic floor disorders in an US-American study. 12.8% of women who never had given birth reported urinary incontinence, while women after one delivery experienced urinary incontinence in 18.4%. This number increases to 32.4% after three births. The frequency of pelvic floor disorders rises regardless of the mode of delivery, while instrumental delivery bears the highest risk to develop pelvic floor disorder [3]. In general, the incidence of pelvic floor disorders is higher in Eurasian females compared to African females and also higher in overweight women compared to women with normal weight. About every 9th woman will need descensus surgery in her lifetime [4], with 29% needing relapse surgery [5].

## **3. Etiology and pathogenesis**

Pelvic floor disorders are multifactorial. Damage to the muscles, ligaments and fasciae of the pelvic floor leads to loss of function. Human's upright gait already leads to a certain stress on the pelvic floor. Furthermore, chronic overload in the context of prolonged high physical stress, obstetric trauma and hereditary connective tissue weakness can lead to prolapse. While chronic overload usually leads to overstretching of the pelvic floor's muscles and fasciae, birth trauma causes tearing of these structures. While the risk for developing a pelvic floor disorder is highest for instrumental delivery, cesarean section and pregnancy itself already increase the risk. Still, prevalence of prolapse is approximately twice as high in women after vaginal birth compared to women after cesarean section [6]. Stress urinary incontinence usually occurs after the bladder neck loses support and through urethraurethral hypermobility as well as weakness of the urinary sphincter. The pathogenesis of urgency incontinence is more complex, which makes it also more complicated to treat. Mechanism contributing to urgency incontinence are detrusor overactivity, poor detrusor compliance and bladder hypersensitivity [7]. Furthermore, neurological damage of somatic and vegetative nerves should always be considered as a reason for pelvic floor disorders. Pelvic floor prolapse usually

only become symptomatic in later stages (when reaching to the vaginal introitus) or when accompanied by anal or urinary incontinence.
