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).