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Background & Objective: Labor pain is one of the most severe pains that mothers experience. Intense pain leads to stress and has unfavorable effects on the mother and fetus. This research was done to determine the effect of using Entonox (N2O) self administration on reducing labor pain in the active phase of labor& delivery, Mode of delivery, and newborn's Apgar score.
Methods: One hundred and twenty primiparous women in 29 Bahman Hospital in Tabriz were included it this randomly single-blind research. In the active phase of delivery, Entonox and Oxygen gases were used. The severity of the mother's pain was asked and was scored according to analogue criterion.
Results: There was a significant difference in frequency of pain intensity in two groups of Entonox and Oxygen. The Mean score of pain intensity in Entonex user, in the first & second stage of labor was 5.93% and 5.82% respectively, while for the oxygen users it was 6.99% and 6.74% which was significant. 41.7% of the mothers in the Entonox group had a severe pain and 11.7% had a very severe pain, whereas in the Oxygen group 58.3% of the mothers had a severe pain and 25% of them had very severe pain (p< 0.001). Meanwhile we found no significant difference between modes of delivery progress of labor and newborn's Apgar
score.
Conclusion: According to research results, Entonox reduces the intensity of labor pain more than oxygen and is effective during the first and second phase of delivery.