Postpartum Perineal Pain After Obstetric Anal Sphincter Injuries

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. One of the most distressing immediate complications of this severe perineal injury is 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.

The objective of this study is to assess the incidence of perineal pain in postpartum patients 1 week after obstetric anal sphincter injuries.

Inclusion Criteria:

• Age >18 years of age
• English-speaking
• Vaginal delivery (spontaneous or assisted)
• A full-term fetus (>37 weeks' gestation)
• OASIS as assessed by obstetrical provider
• Functional epidural analgesia at time of delivery
• Patient amenable to follow-up in specialty perineal clinic within the first week postpartum

Exclusion Criteria:

• Previous pelvic surgery
• History of chronic pelvic pain
• History of recurrent urinary tract infections
• Women with known malformations of their urinary tract
• True allergies to ketamine and/or morphine
• Preeclampsia or hypertensive disorder at the time of delivery
• Obstructive sleep apnea