Comparison of Vaginal and Oral Doses of Misoprostol for Labour Induction in Post-Term Pregnancies.

INTRODUCTION: Considering maternal complications, it is preferred to induce labour after 40 weeks. Labour induction is a procedure used to stimulate uterine contractions during pregnancy before the beginning of the labour.

AIM: The aim of this study was to compare oral misoprostol with vaginal misoprostol for induction of labour in post-term pregnancies.

MATERIALS AND METHODS: This double blind clinical-trial study was performed on 180 post-term pregnant women who were admitted to the labour ward of Besat Hospital Sanandaj, Iran in 2013-2014. Participants were equally divided into three groups using block randomization method. The induction was performed for the first group with 100 μg of oral misoprostol, for the second group with 50 μg of oral misoprostol, and for the third group with 25 μg of vaginal misoprostol. Vaginal examination and FHR was done before repeating each dose to determine Bishop Score. Induction time with misoprostol to the start of uterine contractions, induction time to delivery, and mode of delivery, systolic tachycardia, hyper stimulation and fetal outcomes were studied as well.

RESULTS: First minute Apgar scores and medication dosage of the study groups were significantly different (p=0.0001). But labour induction, induction frequency, mode of delivery, complications, and 5 minutes Apgar score in the groups had no significant difference (p>0.05). The risk of fetal distress and neonatal hospitalization of the groups were statistically significant (p=0. 02). There was no significant difference between the three groups in terms of mean time interval from the administration of misoprostol to the start of uterine contractions (labour induction), the time interval from the start of uterine contractions to delivery and taking misoprostol to delivery. From the administration of misoprostol to start of the uterine contractions the mean difference between time intervals in the three groups were not statistically significant.

CONCLUSION: Based on our findings it can be concluded that prescribing 100μg oral misoprostol is effective than 50 μg oral or 25 μg vaginal misoprostol in terms of induction time, maternal and neonatal outcomes in post- term pregnancy. However, the best dose and route should be decided according to evidence based information.