Risk factors associated with anal sphincter tear difference among midwife, private obstetrician, and resident deliveries.

To identify risk factors that account for the difference in anal sphincter tear (AST) among midwife, private obstetrician, and resident deliveries. We performed a retrospective review of our obstetrical database and used logistic regression analysis to identify risk factors for AST. The relationship between delivery technique and AST was evaluated by comparing AST increase between vaginal deliveries without and with an episiotomy among the three categories of providers. After adjusting for risk factors, private obstetricians (OR: 1.81, 95% CI: 1.27-2.56) and residents (OR: 1.60, 95% CI: 1.20-2.15) had a higher rate of AST during vaginal delivery than midwives. Episiotomy increased the odds of AST by four-fold for midwives, two-fold for private obstetricians, and eight-fold for residents. Although midwife and resident's delivery methods were associated with more AST, neither experienced this complication more frequently than private obstetricians. This suggests that midwives and residents probably misdiagnosed some AST.