A retrospective study of the incidence and predisposing factors of third- and fourth-degree perineal tears

OBJECTIVES: To evaluate the rates of third- and fourth-degree tears and related predisposing factors for the tears in singleton vaginal deliveries. METHODS: This was a retrospective study of third- and fourth-degree perineal tears in all women who underwent vaginal delivery in a tertiary hospital in Assir region between January 2014 and December 2019. There are approximately 5000 deliveries per year at the Abha Maternity and Children Hospital. The total number of deliveries during the study period was 31,788, of which 19,374 were delivered vaginally. RESULTS: A total of 85 women (0.43% of all vaginal deliveries) had third-degree (n=81) or fourth-degree (n=4) perineal tears. The mean age of the women was 31 years (range: 16-46 years). Fifty-two of the 85 women (61%) were primiparous. Of the various obstetric parameters, episiotomy, occipitoposterior presentation, primigravida, multipara, and a previous episiotomy were found to be significant predisposing factors to third- and fourth-degree tears in our patients. CONCLUSION: The low incidence of obstetric anal sphincter injuries in this study is likely the result of proactive manual protection of the perineum, valid indications for episiotomy, and attendance of senior staff members at all difficult deliveries.