Primary: Third/fourth degree tear of maternal anal sphincter (superiority co-primary outcome). Caesarean section (non-inferiority co-primary outcome).
Secondary: Successful vaginal delivery with first instrument, neonatal morbidity, maternal childbirth experience, incontinence, breastfeeding and post-traumatic stress disorder (PTSD) symptoms.
Qualitative Process Evaluation: Explore experiences of trial processes for women and healthcare professionals.