Obstetric interventions and pelvic floor disorders - Abstract One of the principal objectives of obstetric interventions in the second stage of labor is prevention of pelvic floor trauma and associated pelvic floor disorders. The most commonly used and also most frequently discussed interventions are manual perineal protection and episiotomy. The majority of pelvic floor disorders are of subjective nature. Therefore, tools for objectification and severity quantification of these disorders are the key to reliable comparison and identification of the most effective interventions. The aim of the dissertation was to find the most effective modification of manual perineal protection, to compare two frequently used types of episiotomy regarding all pelvic floor disorders and finally to find a consensus on the most suitable instrument for anal incontinence severity assessment. Our studies concerning manual perineal protection experimentally described the direction and extent of perineal deformation during vaginal delivery. The subsequent studies on biomechanical model demonstrated that the most effective method of manual perineal protection in peak perineal strain reduction is when the fingers are placed on the perineum 6 cm laterally and 2 cm ventrally from the posterior commissure at both sides and are...