Perineal Tear Management

Classification and Prevalence

The American College of Obstetricians and Gynecologists (ACOG) defines four degrees of perineal tears based on the depth and structures involved, with accurate identification being critical to prevent long-term morbidity, including anal incontinence in up to 60% of women with missed or improperly repaired severe tears 1, 2
First-degree tears occur in 5.5-16.4% of vaginal births, second-degree tears in 29.0-35.1%, third-degree tears in 1.8-7.1%, and fourth-degree tears in 0-0.3% 2, 3
Up to 35% of anal sphincter injuries are missed without proper examination 4, 1

The American College of Obstetricians and Gynecologists recommends performing a systematic evaluation, including visual inspection, thorough perineal examination, and mandatory digital rectal examination after every vaginal delivery to detect anal sphincter injuries 5, 1, 2
Ensure adequate lighting and proper patient positioning before beginning the examination 5, 1
Inform the patient about the need and reasoning for the examination 1

For first-degree tears, use skin adhesive or no suturing rather than traditional suturing to reduce pain and procedure time with equivalent functional outcomes 1, 2
For second-degree tears, repair deeper perineal muscle layers with sutures, but if the skin is hemostatic, use skin adhesive or no suturing for the perineal skin to reduce pain, dyspareunia, and improve breastfeeding rates at 3 months 1, 2
For third- and fourth-degree tears (OASIS), immediate referral to an experienced provider is mandatory, and if the primary surgeon is inexperienced, pack the wound and safely delay repair up to 8-12 hours until a specialist is available 4, 3, 1

Repair sequentially from deep to superficial: anorectal mucosa (if fourth-degree), internal anal sphincter, external anal sphincter, rectovaginal fascia, perineal body muscles, vaginal mucosa, and skin 5, 1
Use end-to-end technique with mattress or interrupted sutures using 3-0 delayed absorbable suture for internal anal sphincter repair 5, 1
Use continuous non-locking subcuticular sutures for skin to minimize nerve damage and pain 5

Maintain Foley catheter until postoperative day 1, then perform voiding trial 5, 1
Prescribe stool softeners for at least 2-6 weeks to achieve soft stools and prevent strain 5
Provide acetaminophen and NSAIDs as first-line pain control; reserve opiates only if needed 5
Arrange follow-up within two weeks, ideally in a specialized postpartum perineal clinic 5, 1

If wound infection or dehiscence occurs, administer second- or third-generation cephalosporin, or metronidazone with gentamicin (clindamycin for penicillin allergy) for adequate coverage of vaginal and bowel flora 5
For OASIS dehiscence, refer to a specialized postpartum perineal clinic for expert evaluation, and resuturing should only be performed by experienced providers using the same meticulous technique as primary repair 5

OASIS is associated with 29-53% flatal incontinence and 5-10% fecal incontinence in the first 6 months postpartum, causing embarrassment, social isolation, and significantly affecting quality of life 4, 3, 1
Wound complications after OASIS lead to worsened physical, emotional, and sexual satisfaction persisting up to 9 months postpartum 3, 1
Risk increases with missed diagnosis, inappropriate repair technique, and lack of surgeon experience 4, 3, 1