Objectives : Assessing the impact of prolonged latence phase on the progress of labor, the mode of delivery and the neonatal outcomes. Materials and methods : Retrospective study review between July, 1st 2009 and October, 31st 2010 in the maternity of Port Royal and St Vincent de Paul, of 100 patients under Nalbuphine and 91 patients having received an early epidural analgesia following the prolonged latence phase. Results : Significantly more primiparae were observed in the Nubain® group as compared to the epidural analgesia group. Bishop score of Nubain® group patients is less favorable, their labor is longer (5,21 vs 3,16 hours), more dysfunctional labor has been reported (21% vs 6%), as well as more cesarean sections (20% vs 8%). However, the Nubai®* group patients have less meconial fluid (5% vs 15%) and scalp pH (5% vs 20%). These differences are significant. Moreover, 3 times as many postpartum hemorrhages have been reported in the epidural analgesia group. Neonatal outcomes are not statiscally different. Conclusion : The prolonged latence phase of labor is associated with an increased cesarean section risk as a result of dysfunctional labor, without adverse effects on neonatal outcomes.