comparison of epidural versus entonox for labor analgesia in nulliparous women

introduction: the aim of this study is to compare the efficacy of epidural versus entonox methods for labor analgesia in nulliparous women.  methods: this randomized controlled trial was performed on 84 nulliparous women with - pregnancy admitted to imam reza hospital in 10 may 2010- 10 may 2011.  they were randomly divided into two groups 42 women inhaled entonox in active phase at the beginning of each contraction, and for 42 cases, epidural catheter was inserted and analgesic substance was injected and it was increased adjusted with contraction progressing by bupivacaine combined with fentanyl. the rate of pain was measured with pain scores (minimum pain 0 and maximum pain 10).  results: in epidural analgesia, pain score was lower in all stages of labor than entonox analgesia 42% of cases had no pain, while as in entonox group, pain has been decreased 4 scores in 7% of cases and there was no complete analgesia. duration of different stages of labor was not statistically different between two groups (p=0.89). cesarean rate was similar in two groups. first and five minute apgar were not statistically different between two groups (p=0.87, p=0.75, respectively).  conclusions: epidural analgesia with more relief in labor pain is the desired method. this method doesn’t cause more cesarean rate or prolonged labor duration. although entonox decreases labor pain in first stage, but doesn’t affect on second stage and fetus apgar.