What is the perineum and what is its role in vaginal birth?

The perineum is the skin and muscle located between the opening of the vagina and the anus that spans between the sit bones.

During birth, the perineum must stretch downward and outward to accommodate the passage of the baby. 

What is a perineal laceration or "tear?" What are the different types of perineal trauma?

If the perineum is stretched beyond its capacity during a vaginal birth, it will tear to some degree in order to allow the baby's passage. This is similar to a muscle tear experienced elsewhere in the body when a muscle is pushed past a length that it can accommodate.

Perineal trauma is graded from 1-4, based on structures involved in the injury.

     1st degree: Involves the skin and may or may not require sutures (stitches)

     2nd degree: Involves the muscle of the perineum and typically requires sutures

     3rd degree: Involves the perineal and anal muscles and may require surgical repair

     4th degree: Involves the perineal muscle and continues through the anal sphincter to the lining of the rectum, requiring surgical repair

Is tearing common? 

Research shows that a majority of people experience perineal trauma with vaginal birth, with 30-79% of women requiring sutures to repair a laceration following birth. 

Aasheim 2011, Albers 2005, Beckmann 2013, Dunn 2015

What is an episiotomy?

An episiotomy is an incision made into the perineum by a physician in order to widen the vaginal opening for delivery. It will require sutures to repair following birth. While more research is needed regarding the role of episiotomy in birth, the American Congress of Obstetrics & Gynecologists (ACOG) states that the use of episiotomy during labor should be restricted. 

What is the effect of a perineal tear on postpartum pelvic floor function?

Evidence suggests that people with significant perineal lacerations are more likely to report the following postpartum symptoms 

  • Urinary incontinence (unwanted leaking of any amount of urine)

  • Anal incontinence (unwanted leaking of gas or stool)

  • Pain with intercourse and/or chronic pelvic pain

  • Higher risk for postpartum depressive symptoms 

Albers 2005, Eogan 2006, Pergialiotis 2014

What can I do to decrease my risk of tearing?

  • Perform perineal preparation techniques

  • Apply warm compresses to the perineum during the second stage of labor

  • Birth your baby in sidelying or on hands and knees

Aasheim 2011, Kopas 2014

What factors increase the risk of perineal tearing with vaginal birth?

  • Those having their first vaginal birth

  • History of vaginismus (a form of painful sex)

  • Those of Asian descent

  • Those with a previous 3rd or 4th degree perineal laceration

  • High maternal weight gain in pregnancy

  • Fetal birth weight over 8lbs

  • Abnormal fetal positioning at birth 

  • Labor induction or augmentation (administration of Pitocin) 

Pergialiotis 2014, Rosenbaum 2012, Yogev 2014, Jango 2014

The following factors do not have a clear effect on risk:

  • Maternal age 

  • Water birth may be associated with lower risk of severe lacerations and higher incidence of intact perineum after birth. 

  • While epidurals have been shown to increase rates of forceps or vacuum-assisted deliveries, their effect on the risk of perineal trauma is inconclusive.

  • There is not strong evidence to support a specific method or timing of pushing to decrease risk of tears. However, Valsalva pushing (while holding breath) is associated with an increased frequency of abnormal urodynamics at 3 months postpartum when compared to spontaneous pushing (without holding breath). This means that there may be a greater incidence of negative effects on the bladder and pelvic floor muscles.

Vale de Castro 2015, Nutter 2014, Lowenberg-Weisband 2014, Lemos 2015, ACOG Opinion 2017

Aasheim V, Nilsen AB, Lukasse M, Reinar LM. Perineal techniques during the second stage of labour for reducing perineal trauma. Cochrane Database Syst Rev. 2011;(12):CD006672. 

Albers L, Sedler, Bedrick E, Teaf D, Peralta P. Midwifery Care Measures in the Second Stage of Labor and Reduction of Genital Tract Trauma at Birth: A Randomized Trial. J Midwifery Womens Health 2005;50(5):365-372.

Approaches to limit intervention during labor and birth. Committee Opinion No. 687. American College of Obstetricians and Gynecologists. Obstet Gynecol 2017;129:e20-8.

Beckmann MM, Stock OM. Antenatal perineal massage for reducing perineal trauma. Cochrane Database of Systematic Reviews 2013, Issue 4. Art. No.: CD005123. DOI: 10.1002/14651858.CD005123.pub3.

Dunn A, Paul S, Ware L, Corwin E. Perineal Injury During Childbirth Increases Risk of Postpartum Depressive Symptoms and Inflammatory Markers. J Midwifery and Women’s Health 2015;60(4):428-436.

Eogan M, Daly L, O’Herlihy C. The effect of regular antenatal perineal massage on postnatal pain and anal sphincter injury: a prospective observational study. J Matern Fetal Neonatal Med 2006; 19(4):225-9.

Jango H, Langhoff-Roos J, Rosthoj S, Saske A. Modifiable risk factors of obstetric anal sphincter injury in primiparous women: a population-based cohort study. Am J Obstet Gynecol. 2014 Jan; 210(1):59.e1-59.e6.

Kopas M. A Review of Evidence Based Practices for Management of the Second Stage of Labor. J Midwifery & Women’s Health 2014; 5(3): 264-276.

Lemos A, Amorim MM, Dornelas de Andrade A, de Souza AI, Cabral Filho JE, Correia JB. Pushing/bearing down methods for the second stage of labour. Cochrane Database Syst Rev. 2015 Oct 9;10:CD009124.

Loewenberg-Weisband Y, Grisaru-Granovsky S, Ioscovich A, Samueloff A, Calderon-Margalit R. Epidural analgesia and severe perineal tears: a literature review and large cohort study. J Matern Fetal Neonatal Med. 2014;27(18):1864-9.

Nutter E, Meyer S, Shaw-Battista J, Marowitz A. Waterbirth: An Integrative Analysis of Peer-Reviewed Literature. J Midwifery Womens Health 2014;59:286-319.

*Pergialiotis V, Vlachos D, Protopapas A, Pappa K, Vlachos G. Risk factors for severe perineal lacerations during childbirth. Int J Gynecol Obstet 2014;125:6-14.

Rosenbaum TY, Padoa A. Managing pregnancy and delivery in women with sexual pain disorders. J Sex Med 2012;9:1726–1735.

Vale de Castro Monteiro M, Pereira GM, Aguiar RA, Azevedo RL, Correia-Junior MD, Reis ZS. Int Urogynecol J. 2015 Jul 30.

Yogev Y, Hiersch L, Maresky L, Wasserberg N, Wiznitzer A, Melamed N. Third and fourth degree perineal tears - the risk of recurrence in subsequent pregnancy. J Matern Fetal Neonatal Med. 2014 Jan;27(2):177-81.