Extra-amniotic saline infusion increases cesarean risk versus other induction methods and spontaneous labor

Extra-amniotic saline infusion (EASI) via a Foley catheter has been thought to be comparable in efficacy to other induction and cervical ripening methods. This study examines the risk of cesarean delivery associated with EASI compared with spontaneous labor and other methods of cervical ripening. A retrospective cohort study based upon deliveries at Bellevue Hospital Center from August 2000 to December 2002 was conducted. Three groups were identified: EASI, other methods of induction such as prostaglandins and oxytocin administration, and spontaneous labor. Pairwise comparisons were performed using analysis of variance and multivariate logistic regression analysis to control for confounding variables. There were 625 charts evaluated: including 171 with EASI, 190 with other induction methods, and 264 with spontaneous labor. The rates of cesarean section were 33.9%, 17.9%, and 7.2%, respectively. When compared with spontaneous labor, there was a higher risk of cesarean delivery for subjects induced with other methods (adjusted odds ratio [OR], 2.4; 95% confidence interval [CI], 1.3 to 4.5; P < 0.001), and for those induced with EASI (adjusted OR, 5.5; 95% CI, 3.1 to 9.9; P < 0.001). When EASI was compared with other methods of induction, the risk of cesarean delivery was still increased (adjusted OR, 2.3; 95% CI, 1.4 to 3.8; P = 0.001). EASI is associated with an increased risk of cesarean delivery compared with spontaneous labor and other methods of cervical ripening.