Progress of labor in women induced with misoprostol versus the Foley catheter

OBJECTIVE: To estimate and compare the duration and progress of labor in women induced with misoprostol vs Foley catheter plus oxytocin. STUDY DESIGN: We performed a retrospective cohort study of labor progress among 617 consecutive term pregnancies induced with misoprostol (n = 503) or Foley catheter plus oxytocin (n = 114) who completed the first stage of labor. Labor duration and progress in the entire cohort, and stratified by parity, were compared in multivariable interval-censored regression models adjusting for maternal obesity and birthweight. Repeated-measures analysis with 9th degree polynomial modeling was used to construct average labor curves. RESULTS: Total duration of labor was not significantly different in women induced with misoprostol compared with the Foley catheter (median duration from 1 to 10 cm: 12 vs 14.2 hours, P = .19). Progress from 1 to 4 cm was more rapid with the Foley catheter (median: 3.4 vs 5.6 hours, P < .01), although progress from 4 to 10 cm was slower (median: 6.3 vs 3.6 hours, P < .01). Labor curves demonstrated transition from latent to active labor at about 4 cm cervical dilatation with misoprostol and at 6 cm for the Foley catheter. Similar general patterns were noted for nulliparous and multiparous women, except for a shorter duration of labor with the Foley catheter among multiparous women. CONCLUSION: Induction of labor with the Foley catheter is associated with more rapid initial cervical dilation, but transition to active labor occurs later compared with misoprostol. These differences should be considered in the management of induced labor.