Third degree anal sphincter tears: risk factors and outcome.

The aim of this retrospective study was to determine the incidence, risk factors and anal symptoms related to third degree tears after vaginal delivery. There were 9,631 vaginal deliveries during the 5-year period studied, with 116 (1.2%) having a third degree tear. Statistically significant risk factors for a third degree tear were primiparity, forceps delivery, episiotomy, fetal birth-weight greater than 4,000 g and increased duration of the second stage of labour. Eighty four of the 116 women were able to be interviewed, and 21 (25%) had anal symptoms related to the tear. Only 3 women had sought help for their symptoms. Twelve women experienced anal incontinence and 2 more required delayed repair of the anal sphincter for incontinence. Third degree tears are a major cause of perinatal and postnatal morbidity. Attention needs to be directed to the prevention of such tears by awareness of the women at risk and to better follow-up and counselling of the women sustaining a tear.