Postpartum Perineal Pain after Obstetric Anal Sphincter Injuries: A Randomized Clinical Trial

Obstetric anal sphincter injuries (OASIS) encompass both third and fourth degree perineal tears. These tears can have a significant impact on women's quality of life in the short and long term. The immediate complication of this severe perineal injury is unrelenting perineal pain. Women can also experience postpartum depression, dyspareunia, and altered sexual function after OASIS. This is a randomized controlled trial to study the effects of three interventions (placebo, low dose intravenous ketamine plus epidural morphine, or epidural morphine alone) on acute pain after OASIS.