| Background and aim: Entonox was one of the important methods for pain management in the delivery process.
In previous years some studies have assessed the effect of this method in Iran. In this regard, the aim of this study
was to systematically review studies addressing the effect of Entonox for pain management in labor.
Methods: This systematic review and meta-analysis study was conducted in 2016. The required data was
collected using keywords such as ”Entonox”, “nitrous oxide”, ”vaginal delivery”, ”pain relief”, “obstetric”, “labor
pain”, and “labor analgesia”, from databases including Google scholar, PubMed, Science Direct, Magiran, SID,
and Scopus, and hand-searching of related and valid journals and references of articles. Articles published from
2000 to 2016 were searched. To conduct meta-analysis, CMA:2 (Comprehensive Meta-analysis) was used.
Results: Finally, 14 articles were included in the study. Pain relief standard difference in mean between-groups
was -1.01 (95% CI: -1.59 to -0.43, Q=148.5, df=8, p=0.02, I2=76) this difference was significant (p<0.05). The
overall Apgar score standard difference in mean between-groups (Entonox vs. comparison) was 0.12 (95% CI:
0.01 to 0.23, Q=109.4, df=16, p=0.00, I2=85.3) this difference was significant (p<0.05). The results of mothers’
satisfaction rate show that mothers in Entonox group has a high level of satisfaction rate.
Conclusion: According to results of studies published in Iran, it seems that Entonox is an effective method for
pain relief in vaginal delivery, as well as for improving infant Apgar score and mothers’ satisfaction rate. Pain
relief through Entonox can be used as a strategy for cesarean section reduction plan in Iran |