Risk factors for Anal Sphincter Tears

Background: To determine risk factors in cases of thirdand fourth degree anal sphincter damage during vaginaldeliveries.Methods: In this descriptive study all women withrecognized third or fourth degree perineal tear wereincluded .The main outcome measures were relationshipwith parity, weight of baby and mode of delivery.In allpatients end to end anastomosis technique was used torepair the tear.Results: A total no of 57(1.8%) were identified to havesustained anal sphincter complex damage out of 3076vaginal deliveries. The mean age was 25.65 +_4.6 years.Majority 52 (91.2%) were between 20-35 years and 3 (5.26%)> 35years.Most commonly the tears were seen in patientsof reproductive age group. The primipara or primigravidashad highest frequency of anal sphincterdamage(71.9%).Thirty three (57.9%) had spontaneousvaginal deliveries (SVD) , 11 (19.3%) SVD withepisiotomy, 11 (19.3%) forceps and 1 (1.75%) vacuumdelivery. Majority (63.16%) delivered babies between 2500-3500 grams.Conclusion: Anal sphincter damage is stronglyassociated with first vaginal delivery. Forceps delivery ascompared to vacuum delivery has higher rate of third andfourth degree tears. Mediolateral episiotomy may haveprotective role