Third and fourth degree tears

Clinical commentary

Severe perineal trauma is defined as a third degree tear, which involves injury to the perineum which extends to the anal sphincter muscles; or a fourth degree tear, which involves injury to the perineum involving the external, internal and epithelium of the anal sphincter (RCOG 2015).  Severe trauma to the perineum can occur spontaneously or as a result of obstetric intervention during vaginal birth.

Severe perineal trauma is associated with maternal morbidity such as perineal pain, incontinence and subsequent difficult or painful sexual intercourse, and rarely, recto-vaginal fistula (RCOG 2015). The significant psychological effects of severe perineal trauma are under-researched but likely to be significant for many women in this situation (Priddis et al. 2013). 

Risk factors during the antenatal period associated with an increased incidence of severe perineal trauma include nulliparity, young maternal age, ethnicity and poor nutritional status, high fetal weight, as well as previous experience of perineal tear (Dahlen et al. 2013).  Intrapartum risk factors include fetal malpresentation (for example occipito-posterior position), episiotomy (especially midline), instrumental vaginal birth, prolonged second stage of labour, birth position and shoulder dystocia (Eskandar & Shet 2009; Hartman et al. 2005; Kudish et al. 2008; O’Mahony et al. 2010).

Indicator specifications and data

Excel source data tables are available from the Data tab.

For more information refer to Specifications and notes for analysis in the technical notes.


  • Dahlen H, Proddis H, Schmied V, Sneddon A, Kettle C, Brown C & Thornton C 2013. Trends and risk factors for severe perineal trauma during childbirth in New South Wales between 2000 and 2008: a population-based data study. British Medical Journal Open 3(5): e002824.
  • Eskandar O & Shet D 2009. Risk factors for 3rd and 4th degree perineal tear. Journal of Obstetrics and Gynaecology 29:119–22. 
  • Hartman K, Viswanathan M, Palmieri R, Gartlehner G, Thorp J & Lohr KN 2005. Outcomes of routine episiotomy: a systematic review. JAMA 293:2141–8. 
  • Kudish B, Sokol RJ & Kruger M 2008. Trends in major modifiable risk factors for severe perineal trauma, 1996–2006. International Journal of Gynaecology and Obstetrics 102:165–70. 
  • O’Mahony F, Hofmeyr GJ & Menon V 2010. Choice of instruments for assisted vaginal delivery. Cochrane Database Systematic Review 11:CD005455. 
  • Priddis H, Dahlen HG & Schmied V 2013. Women’s experiences following severe perineal trauma: a meta-ethnographic synthesis. Journal of Advanced Nursing 64:748–59. 
  • RCOG (Royal College of Obstetricians & Gynaecologists) 2015. The management of third- and fourth-degree perineal tears (Green-top guideline No. 29). UK: NICE.