Predictors of episiotomy use at first spontaneous vaginal delivery

Objective: To identify factors associated with the use of episiotomy at spontaneous vaginal delivery. Methods: We studied 1576 consecutive term, singleton, spontaneous vaginal deliveries in nulliparas at Brigham & Women's Hospital between December 1, 1994 and July 31, 1995. The association of demographic variables and obstetric factors with the rate of episiotomy use were examined. Adjusted odds ratios (OR) and confidence intervals (CI) were estimated from multiple logistic regression analysis. Results: The overall rate of episiotomy was 40.6% (640 of 1576). Midwives performed episiotomies at a lower rate (21.4%) than faculty (33.3%) and private providers (55.6%) (P = .001). After controlling for confounding factors with logistic regression, private practice provider was the strongest predictor of episiotomy use (OR, 4.1; 95% CI, 3.1, 5.4) followed by faculty provider (OR, 1.7; 95% CI, 1.1, 2.5), prolonged second stage of labor (OR, 1.8; 95% CI, 1.2, 2.7), fetal macrosomia (OR, 1.6; 95% CI, 1.1, 2.5), and epidural analgesia (OR 1.4, 95% CI, 1.1, 1.8). Conclusion: The strongest factor associated with episiotomy at delivery was the category of obstetric provider. Obstetric and demographic factors evaluated did not readily explain this association. (C) 2000 by The American College of Obstetricians and Gynecologists.