Obstetric rectal injury: risk factors and the role of physician experience

Objective: To identify the risk factors for rectal injury following vaginal delivery and to determine the impact of accoucheur experience (resident vs. attending) on those risk factors. Methods: A database at our institution was used to identify women with a singleton gestation, vertex presentation, and no prior cesarean delivery who underwent a vaginal delivery over a three year period. The outcome of interest was rectal injury. We performed logistic regression evaluating the association of parity, birthweight, forceps, vacuum, midline episiotomy, epidural anesthesia, and operator status with rectal injury. We calculated population attributable risk to estimate the relative contribution of each risk factor. Results: A total of 17 722 women met the inclusion criteria. The frequency of rectal injury was 8.9% (n = 1572). Our data demonstrate a significant increase in risk of rectal injury with birthweight > 4000 g, midline episiotomy, or operative vaginal delivery. Multiparity is significantly protective from rectal injury. Neither epidural anesthesia nor operator status altered the risk of rectal injury. The population attributable risk of each risk factor for rectal injury was similar regardless of operator group. Conclusion: The risk factors for rectal injury were present regardless of operator status, and the factors contributed to a similar extent for each group.