Aims: There is a considerable increase in the maternal and infancy mortality and side-effects in accordance with higher pregnancy ages. Due to such a risk, it is nedded to statrt the labor induction from week 40. Misoprostol is one of the medications used in such conitions. The aim of this study was to compare the effects of oral misoprostol and vaginal misoprostol in the labor induction in the prolonged pregnancy. 

Materials & Methods: In the two-blinded random climical trial, 180 pregnant women with more than 40 weeks gestational age referred to the labor ward of Sanadaj Besat Hospital were studied in 2013-2014. The samples were selected via randomized blocking sampling method. Through sixtuple random blocking method, the subjects were divided into three groups including 50μg oral misoprostol, 100μg oral misoprostol, and 25μg vaginal misoprostol. Having been recorded on a checklist, data was analyzed by SPSS 18 software using one-way ANOVA, Chi-square, and Fisher’s exact tests.

Findings: There were significant differences between the mean 1^st minute Apgar score and the medication consumption dose in the groups (p=0.0001). There were no differences between the groups in the mean 5^th minute Apgar score, induction frequency, induction times, mode of delivery, and its side-effects (p>0.05). Nevertheless, there were significant differences in fetal distress frequency and the infant hospitalization (p<0.05). There were no significant differences in the mean interval between misoprostrol consumption and the delivery time between the groups (p=0.28).

Conclusion: Considering the labor induction time and maternal and infancy outcomes, administration of 100μg oral misoprostrol in the prolonged pregnant women is more useful than 50μg oral misoprostrol and 25μg vaginal misoprostrol.