The Effect of Entonox Gas Inhalation on the Duration of Active Phase of Labor and Outcome of Delivery

Document Type : Original Article


1 Department of Obstetrics & Gynecology, Fertility Infertility and Perinatology Research Center, Ahvaz Jundishapur University of Medical Sciences. Ahvaz. Iran

2 Department of Obstetrics & Gynecology,Tamin Ejtemaee Hospital of Borujerd, Borujerd, Iran.


Background and Objective: Annually, thousands of the elective caesarean sections are performed that the fear of labor pain is considered as the major underlying cause. Various methods are introduced for pain relief during labor. Prolongation of labor is one of the complications of some painless labor methods. The aim of this study was to investigate the effect of Entonox inhalation as a type of labor analgesia, on the duration of the active phase of labor and outcome of delivery.
Subjects and Methods: This is a clinical trial study which was performed on 200 pregnant women at the maternity ward of Ahvaz Emam Khomeini hospital. The women were randomly divided into two equal case and control groups (n= 100). The case group inhaled Entonox with a mask from the start of the active phase of labor, and the delivery was performed for the control group without Entonox use.
Result: The duration of active phase of labor in the case group was significantly shorter than the control group (4.07±2.1 hours in study group in comparison with 5.12±2.06 hours in control group). Furthermore us          e of Entonox not only caused decrease in the labor pain and increases in mothers' satisfaction, but also did not influence on the APGAR of the neonates.
Conclusions: The finding of this study demonstrated that Entonox gas is an effective and a safe method for relief of labor pain. In addition not only it reduces duration of active phase of labor, but also increases mothers' satisfaction.


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