Objective: The aim of this randomized controlled Study was to compare the efficacy and the safety of different regimens of misoprostol for labor induction. Material and methods: Eligible women received intravaginal 100 mug, every 6 h or 50 mug every 4 h. Treatment continued Until: (I) dilatation >3 cm (2) rupture of membranes (artificial); (3) Signs Of Uterine hyperstimulation; (4) adequate contraction pattern (three contraction/10 min). Managing clinician Might Use oxytocin during labor. Cesarean section rate was the Main outcome that was considered variably. Other outcome measures were neonatal outcome (Apgar scores, meconium staining, and Urnblical artery pH) and induction to delivery interval. Results: A total number of 72 women received either misoprostol 100 mug (n - 37), or 50 mug (n = 35) randomly. The two groups had smiliar mean Bishops scores at induction (4.10 +/- 2.4 versus 4.2 +/- 2.1; P - 0.85), rates of nulliparity, Use of epidural anesthesia, and oxytocin augmentation. In two groups the number of closes of inisoprostol used was smiliar ( 1.6 +/- 0.5 versus 1.7 +/- 0.3) Conclusion: There was not any difference between the two groups in the mean +/- S.D. time to delivery (h) and cesarean rate. Likewise, there was not a significance between two groups in the rates of 5 min Apgar score, and of meconium passage. (C) 2003 Elsevier Ireland Ltd. All rights reserved.