Lacerations to the perineum most commonly occur following a rapid, uncontrolled delivery of the fetal head. Postpartum perineal lacerations range from minor to severe. First-degree lacerations are limited to the mucosa, skin, superficial subcutaneous, and submucosal tissues. Second-degree lacerations penetrate deeper into the superficial fascia and transverse perineal musculature. Third-degree lacerations extend through deeper tissues and disrupt the anal sphincter, while fourth-degree lacerations extend through rectal mucosa. These injuries can be associated with significant maternal blood loss and multiple long-term complications.
Management and Disposition
In ED deliveries, the repair of perineal lacerations can be deferred to an obstetrician, the details of repair being beyond the scope of this book. If maternal blood loss is significant, apply pressure to control bleeding while awaiting definitive repair.
First-Degree Laceration. First-degree laceration limited to the mucosa, skin, and superficial subcutaneous and submucosal tissues. There is no involvement of the underlying fascia and muscle. (Photo contributor: Jerry Van Houdt, MD.)
Warm perineal compresses and manual perineal support during delivery reduce the risk of significant vaginal trauma from birth.
Perineal laceration repair fundamentally involves the sequential anatomic reapproximation of the rectal mucosa, anal sphincter, transverse perineal musculature, vaginal mucosa, and skin using absorbable suture material.
Second-Degree Laceration. There is disruption of the hymenal ring and the deep perineal musculature, extending into the vaginal mucosa and transversalis fascia, but no involvement of the anal sphincter or mucosa. (Photo contributor: Pamela Ambroz, MD.)
Fourth-Degree Laceration. Fourth-degree perineal laceration revealing wide separation of the perineal fascia and anal sphincter. The examiner’s small finger is in the rectal lumen, showing extension of the tear proximally. (Photo contributor: Timothy Jahn, MD.)
Postpartum Perineal Lacerations. These cadaveric photographs illustrate the defining anatomy for first- through fourth-degree perineal lacerations. (A) First, (B) second, (C) third, and (D) fourth. (Photo contributor: Barbara Hoffman, MD.)