Structured Abstract Objective: An investigation of incidence and degree of anal incontinence after vaginal delivery among primiparas and characterizing of the risk factors. Design: Prospective observational study. Setting: Department of Gynecology and Obstetrics, Charles University and Faculty Hospital Pilsen. Methods: 346 primiparas after consecutive vaginal delivery between May 2000 and February 2001 were included. All delivered in lithotomy position. Questionnaires were sent few days after delivery and then two and 6 - 9 months later. Analysis of the returned questionnaires. 28 obstetric parameters assessed. Results: 46.5% women responded. 23 women registered leakage of flatus before delivery.Twomonths postpartum one (0.6%) patient reported fecal incontinence and 22 (14.3%) flatus incontinence de novo or impaired already present incontinence. 6 - 9 months after delivery the same patient (0.6%) reported fecal incontinence and 16 women (10.4%) incontinence of flatus. Ten of them felt impaired quality of life. Anal incontinence gradually improved during the time (in 76%). Risk factors of developing (worsening) of anal incontinence were antenatal anal incontinence (in two months period) and women weight (or BMI) measured at 6 - 9 months after birth. None of nine patients after forceps delivery (Breus traction forceps) which responded reported signs of anal incontinence. Neither the range of episiotomy nor the length of perineum had any relation to the development of anal incontinence. However episiotomy has been shown to be a protective factor of 3rd degree tear in primiparas (RR 0.24). Third degree tear was diagnosed in seven cases (2%), three out of 6 women reported anal incontinence postpartum. Conclusion: This study shows relatively frequent development of flatus incontinence after vaginal delivery in primiparas. These symptoms usually improve within the time. Only minimum of women after vaginal delivery suffers of fecal incontinence. 42% of women with anal incontinence feel impaired quality of life. At the first postpartum check every woman should be asked, whether she has any symptoms of anal or urine incontinence or impaired sexual health. If positive the answer, the woman should get information where to find a help.

        Key words: vaginal birth, anal incontinence, fecal incontinence, episiotomy, perineal injury, forceps