The aim of this research is to establish whether specialised Obstetric Anal Sphincter Injures (OASIS) clinics diagnose and treat post-birth injuries sooner. We are investigating this by focusing on three questions: [1] Does having an OASIS clinic reduce the length of time between giving birth and having a post-birth injury operation? [2] Does having an OASIS clinic increase the number of day case operations as a percentage of the total? [3] Are patients travelling further to a trust with an OASIS clinic in order to have their post-birth operation?