Episiotomy, a component of operative vaginal delivery (OVD), aims to prevent anal sphincter tears and associated sequelae. Robust evidence suggests restrictive use should be adopted at vaginal delivery but poor quality contradictory evidence exists at OVD. This thesis concerns a series of studies conducted to address this gap in knowledge. Formative work established a priori views and current practice of all obstetricians in the UK and Ireland via a national survey. The majority of clinicians preferred routine use of episiotomy at forceps delivery and restrictive use at vacuum. Respondents indicated support for the planned pilot RCT. A feasibility study established the possibility of conducting a pilot RCT with its known complexities. Data collection tools were developed and found to be fit for purpose and acceptable to women. Shortcomings in the study design informed the proposed pilot RCT. Contemporaneous to the pilot RCT, we conducted a prospective cohort study (n=1360) of morbidity in relation to episiotomy use at OVD to contextualise its findings. Episiotomy was not found to be protective of anal sphincter tears, shoulder dystocia or neonatal trauma but was associated with an increased risk of postpartum haemorrhage [adjusted OR 1.72 (95%CI 1.21 – 2.45)], perineal infection [adjusted OR 4.04 (95%CI 1.44 – 11.37)] and analgesic use [adjusted OR 3.35 (95%CI 2.49 – 4.51)]. The two centred pilot RCT, while not powered to provide definitive evidence, suggested a restrictive approach to episiotomy use does not appear to reduce or greatly increase anal sphincter tears [8.1% vs 10.9%, adjusted OR 0.77, (95% CI 0.28 – 2.10)]. There may however be a difference in effect size and direction between vacuum and forceps use. Routine use was associated with an increase in PPH [36% vs 27%; adjusted OR 1.88, (95% CI 0.99 - 3.57)]. A longitudinal follow up of participants to one year postpartum suggested routine use of episiotomy may decrease rates of urinary morbidity, particularly stress incontinence; dyspareunia; and perineal pain compared to restrictive use. This pilot RCT supports current practice regarding approach to episiotomy use at OVD meantime, pending the results of a definitive study.