Introduction & Objective: Decreased labor period can reduce the incidence of cesarean section. The aim of this study was to evaluate the effect of increased hydration on labor in nulliparous pregnant women.

Materials & Methods: This randomized double blind clinical trial was done on 180 nulliparous term pregnant women (GA³37weeks), whose active phase of labor had started. They were grouped as case and control groups. The case group received 250 ml of ringer lactate and control group received 125ml of ringer lactate. The duration of each phase (active and second phases) and total duration of labor, severity of pain by means of visual analogue scale, need of oxytocin, cesarean section ratio and apgar of neonate were studied.

Results: Both phases of labor were significantly less than what was for the other group (p<0.005) and this reduction in period was calculated 66 minutes for active phase and 20 minutes for the second phase. The control group needed to receive oxytocin significantly more than the other one (p<0.001), pain score and cesarean section ratio were significantly less than the case group (p<0.012, p<0.001 respectively). The analysis of the data showed that neonates whose mothers had been hydrated, had a better apgar score than the others (p<0.03).

Conclusion: This study showed that hydration of pregnant women during labor will lead to independently significant reduction in duration of labor and also lower severity of labor pain. According to our results, it is recommended administer in the patients who have no contraindication for hydration, to 250 ml/h intravenous fluid.