Due to their serious impact, third or fourth degree perineal tears are a commonly tracked adverse event in obstetric care (Agency for Healthcare Research and Quality and Joint Commission). As such, incidence data will soon be available to third-party payers and to the public on the Internet. Moreover, functional impairment after perineal lacerations continues to be a significant impetus for legal claims. Thus, reducing OASIS while preserving maternal and fetal outcomes is an important goal in clinical obstetrics.