Objective: To assess the relevance of the suture angle when evaluating mediolateral episiotomy, and the safety of the accepted lower limit of 40 degrees for the incision angle.
Method: The angles formed by the incision and suture lines with the midline were measured, and any perineal tear noted, in 50 consecutive women undergoing their first vaginal delivery.
Results: The angles were significantly different (40 degrees and 22.5 degrees , respectively; P<0.001). The only variable significantly linked to the difference was the timing of the episiotomy.
Conclusion: The suture angle cannot currently be used to assess the adequacy of the incision angle; moreover, an incision angle of 40 degrees is probably too acute to prevent potential sphincter damage.