Third and Fourth Degree Perineal Tears Explained
Published: 15 February 2021
Published: 15 February 2021
Perineal tears, while common and usually minor, may cause significant complications if the injury is extensive.
A perineal tear occurs when the perineum - the area between the vagina and anus - is injured during childbirth (ACSQHC 2019a).
Tears are caused by the fetal head stretching the vagina and perineum during delivery (RCOG 2019a).
While perineal tears are common, occurring in over 85% of vaginal births (Goh, Goh & Ellepola 2018), most do not result in serious injury (ACSQHC 2019a).
However, third and fourth degree perineal tears (also known as severe perineal tears or obstetric anal sphincter injuries), which are experienced by approximately 3% of women giving birth vaginally and 5% of women giving birth vaginally for the first time, are more serious and may lead to complications (ACSQHC 2019a).
Third and fourth degree perineal tears may adversely affect physical, psychological and sexual wellbeing, and sometimes require surgery (ACSQHC 2019a).
While it is possible to reduce the risk of experiencing a perineal tear, they are not completely preventable. However, with effective treatment, including specialised care (if required), most patients who experience tears are able to recover (ACSQHC 2019a).
There are three categories of risk factors: maternal, fetal and intrapartum (relating to labour and birth) (Goh, Goh & Ellepola 2018).
Maternal risk factors include:
(ACSQHC 2019b; Goh, Goh & Ellepola 2018)
Fetal risk factors include:
(ACSQHC 2019b)
Intrapartum risk factors include:
(ACSQHC 2019b; Goh, Goh & Ellepola 2018)
Perineal tears are classified depending on the extent of the injury, with first degree tears being the most minor and fourth degree tears being the most severe (QLD DoH 2018a).
Degree | Description | Treatment | |
---|---|---|---|
1 | A shallow injury that affects the skin only of the vaginal mucosa or perineum. | May heal on its own or require stitches. Recovery is usually within the first few weeks or months after birth. | |
2 | An injury that affects the perineal muscles. | Usually requires stitches. Recovery is usually within the first few weeks or months after birth. | |
3 | An injury that affects the perineal muscles and anal sphincter muscles. There are three sub-classifications: | Usually requires stitches given in an operating theatre under anesthetic. | |
3A | Less than 50% of the external anal sphincter is injured. | ||
3B | More than 50% of the external anal sphincter is injured. | ||
3C | Both the external and internal anal sphincters are injured. | ||
4 | An injury to the perineum that extends through the anal sphincter to the anal epithelium. | Usually requires stitches given in an operating theatre under anesthetic. |
(Goh, Goh & Ellepola 2018; QLD DoH 2018a, b; RCOG 2019b)
Those who experience third and fourth degree perineal tears may experience short-term or long-term adverse effects including:
(ACSQHC 2019b; Ramar & Grimes 2020)
An episiotomy involves making an incision in the perineum to increase the diameter of the vaginal opening. This creates more space for the fetal head, reducing the risk of a third or fourth degree perineal tear (ACSQHC 2019b; Goh, Goh & Ellepola 2018).
The incision made in an episiotomy is similar to a second degree perineal tear (QLD DoH 2018a).
An episiotomy is indicated by the Royal Australian and New Zealand College of Obstetricians and Gynaecologists (RANZCOG) in the following situations:
(RANZCOG 2017)
With the above situations as exceptions, RANZCOG does not encourage the routine use of episiotomy (RANZCOG 2017).
Perineal tears are usually repaired using stitches, with third and fourth degree tears being repaired in an operating theatre under anaesthetic (as this facilitates anal sphincter relaxation) (Goh, Goh & Ellepola 2018).
When a perineal tear is being repaired:
(Goh, Goh & Ellepola 2018; ACSQHC 2019b)
This may include:
(Goh, Goh & Ellepola 2018)
Following repair, the patient may need to be referred to an obstetrician if they are experiencing:
(Goh, Goh & Ellepola 2018)
Strategies to reduce the risk of experiencing a perineal tear include:
(QLD DoH 2018a; ACSQHC 2019b)
During labour and birth, strategies include:
(QLD DoH 2018a)
The Australia Commission on Safety and Quality in Health Care is currently in the process of finalising a new Third and Fourth Degree Perineal Tears Clinical Care Standard. This standard aims to reduce the risk of severe perineal tears and improve the care of patients who experience them (ACSQHC 2019a).
According to the draft document released in 2019, the standard comprises the following seven Quality Statements:
Quality Statement 1: Information, shared decision making and informed consent | Patients are appropriately informed about their birth options (e.g. vaginal birth, instrument-assisted birth, caesarean section) and the possibility of experiencing a third or fourth degree perineal tear. This information is individualised and provided to the patient in a way they can understand. |
Quality Statement 2: Reducing risk during pregnancy, labour and birth | During pregnancy, patients are advised on how to reduce the risk of a severe tear. During labour, the clinician uses evidence-based strategies to reduce the risk. |
Quality Statement 3: Instrumental vaginal birth | When an instrumental delivery is indicated, the clinician considers clinical need and the potential benefits and risks (including the risk of a severe perineal tear). |
Quality Statement 4: Identifying third and fourth degree perineal tears | Patients are examined after vaginal birth for perineal tears. Any identified tears are appropriately classified and documented. |
Quality Statement 5: Repairing third and fourth degree perineal tears | Third and fourth degree tears are quickly repaired in an appropriate environment. |
Quality Statement 6: Postoperative care | Patients receive postoperative care after repair of a severe tear. This should comprise debriefing, physiotherapy and psychosocial support. |
Quality Statement 7: Follow-up care | Patients receive follow-up care after repair of a severe tear to optimise physical, emotional, psychological and sexual health. They are referred to a specialist if required. |
(ACSQHC 2019b)
Note: This information is subject to change upon release of the standard’s final version.
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