What is a third-degree perineal laceration, also known as a severe (third-degree) perineal tear?

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From the Guidelines

A third-degree perineal laceration, also known as a severe perineal tear, is a tear that occurs during childbirth which extends from the vaginal opening through the perineal skin and muscles and into the anal sphincter muscle, involving damage to the external anal sphincter (EAS), internal anal sphincter (IAS), or both, but does not extend into the rectal mucosa, as described in the 2024 study published in the American Journal of Obstetrics and Gynecology 1.

Definition and Classification

This type of laceration is further classified into three subcategories:

  • 3a (less than 50% of the external anal sphincter is torn)
  • 3b (more than 50% of the external anal sphincter is torn)
  • 3c (both external and internal anal sphincter muscles are torn)

Repair and Management

These lacerations require careful surgical repair in layers under adequate anesthesia, typically performed by an experienced healthcare provider in an operating room setting, as emphasized in the 2024 study published in the American Journal of Obstetrics and Gynecology 1. The repair involves identifying and suturing each layer of damaged tissue separately, including the anal sphincter muscles, perineal muscles, and skin. Following repair, patients need close monitoring for complications such as infection, pain, urinary retention, and potential long-term issues like fecal incontinence or sexual dysfunction. Proper postoperative care includes pain management, stool softeners to prevent constipation, antibiotics to prevent infection, and pelvic floor physical therapy to aid healing and restore function, as highlighted in the study 1.

Importance of Early Identification and Repair

Early identification and appropriate repair of third degree lacerations are crucial to minimize long-term complications and preserve anal sphincter function, as noted in the study 1. The severity and morbidity experienced after perineal injury is dependent on the extent of perineal damage, the technique and materials used for repair, and the skill and knowledge of the birth attendant, as discussed in the study 1.

From the Research

Definition of Third-Degree Perineal Laceration

A third-degree perineal laceration, also known as a severe (third-degree) perineal tear, is an injury involving the anal sphincter that occurs during vaginal delivery 2. This type of tear can lead to short- and long-term complications for the mothers, affecting their quality of life.

Characteristics of Third-Degree Perineal Laceration

The characteristics of third-degree perineal laceration include:

  • Involvement of the anal sphincter complex 3
  • Extension into or through the anal sphincter complex 3
  • Increased risk of pelvic floor injury, fecal and urinary incontinence, pain, and sexual dysfunction 3
  • Prevalence of 0.25 to 6% among vaginal deliveries 2

Complications of Third-Degree Perineal Laceration

The complications of third-degree perineal laceration include:

  • Anal incontinence 4, 5
  • Fecal incontinence 4
  • Flatus incontinence 4
  • Pelvic floor injury 3
  • Urinary incontinence 3
  • Pain 3
  • Sexual dysfunction 3

Management of Third-Degree Perineal Laceration

The management of third-degree perineal laceration includes:

  • Primary surgical repair 4
  • Pelvic floor exercises 4
  • Transanal electrical stimulation 4
  • Antibiotic prophylaxis to prevent perineal wound infection 6

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Anal incontinence after obstetric third- /fourth-degree laceration. One-year follow-up after pelvic floor exercises.

International urogynecology journal and pelvic floor dysfunction, 1999

Research

Anal incontinence among women with one versus two complete third-degree perineal lacerations.

International journal of gynaecology and obstetrics: the official organ of the International Federation of Gynaecology and Obstetrics, 2005

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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