Objective: Summary of the mutual relationship between obstetric operations, instrumental vaginal delivery and the third degree tear and anal incontinence. Design: Review. Setting: Department of Gynaecology and Obstetrics, Charles University and Faculty Hospital Plzen, Czech Republic. Summary: Review of the current international literature covering the given problem. Midline episiotomy is a recognized risk factor. The role of mediolateral episiotomy is not quite clear. This could be a preventive factor in 20–30% of all deliveries (particularly at the first delivery). The use of forceps is the most significant risk factor of the third degree tear and anal incontinence. Vacuumextraction should be preferred when possible. There is a paucity of literature addressing the problem of fundal pressure and perineal trauma. In the largest study the relative risk of fundal pressure of the third degree was 1.27. Elective Caesarean is considered to be a prevention of pelvic floor injury and the development of urine and anal incontinence for a certain length of time. Its protective effect seems to die down and ultimately cease over a period 6 years. Endoanal sonography is a reliable method of anal sphincter defect detection. Primary and secondary prevention of anal incontinence is outlined.

        Key words: anal incontinence, perineal trauma, third degree tear, episiotomy, forceps, vacuumextraction, fundal pressure, elective Caesarean section, emergency Caesarean section