The Effect of Continuous Entonox Inhalation on the Length of Labor in Duration of Active Phase of Labor

The second stage of labor is painful and stressful stage for mother and fetus. For this reason various methods have been used for painless labor. Prolonged labor is one of the complications of some painless labor methods. The aim of this study was to investigate the effect of continuous entonox inhalation on duration of active phase and 2nd stage of labor. This is a clinical trial study was performed on 200 women in active phase of labor. The women were randomly divided into case or control groups (100 patients in each group). The case group inhaled Entonox continuously for labor analgesia, and the control group with the same condition inhaled air continuously with mask. Duration of active phase and second stage of labor was compared. Two groups were similar with regard to maternal age, gestational age, parity, mode of delivery and neonatal weight. The duration of active phase of labor in case group was shorter than control group (4.17hr vs 5.07 hr, p<0.05). There was no significant difference in duration of second stage of labor between case group and control group (33.19 min vs 26.70 min. Inhalation of entonox for labor analgesia shortens the duration of active phase of labor but has no effect on second stage of labor.