[RISK FACTORS FOR POSTPARTUM OCCULT INJURIES OF THE ANAL SPHINCTER.]

introduction The overall risk of intrapartum damage the anal sphincter (IUAS) is 1% of all vaginal births. In contrast, the so-called "occult" anal sphincter injuries (OASIS) (defects esablished by endoanal ultrasonography) occur in 33% of primiparous women after vaginal birth. Identifying the most common risk factors for OASIS can be the basis for selecting high-risk patients. These women should be targeted by early pospartum diagnosis and treatment, which could reduce the incidence of anal incontinence developed later in life. Objectives To determine the role of common risk factors for the occurrence of OASIS in selected population. Material and methods The study included 42 patients after vaginal birth, born in Maternity Ljubljana in the period January to June 2009, and 38 patients from July 2009 to November 2011, born in Obstetric Clinic of the University Hospital - Pleven, diagnosed with OASIS using endoanal ultrasonography. Results We demonstrated that all of the independent variables studied in our research (primiparity, gestational age over 41gw and fetal weight over 3500 g.) are risk factors for the occurrence of OASIS. Discussion This sudy shows that the sudied risk factors for the occurrence of OASIS may be included in a clinical practice guideline for eady diagnosis and proper treatment of posTpartal injuries affecting the pelvic floor.