Discussion
Pain, labor pain, ischemia, lumbar disc herniation pain, dysmenorrhea, pain
ISCHEMIA, HEAT, DYSMENORRHEA
The results of the present study showed that the pain intensity at the first stage of labor was lower, in the hot water bag and infrared belt groups than in the control group, while it was lower in the infrared belt group compared to the hot water group.Behmanesh et al. (2009) reported that the pain intensity of the first stage of labor was lower in the hot water bag group than in the routine care group [The mechanism of heat in alleviating pain is well explained in the Gate Control Theory of Pain [To the best of our knowledge, no specific study has been performed to investigate the effect of an infrared ceramic belt on labor pain. However, the results of other studies were indicative of the effectiveness of infrared in alleviation of pain like dysmenorrhea [This study was the first clinical trial regarding using the ceramic belts with infrared merged, as a non-pharmacological method and complementary medicine, which was safe and effective in relieving labor pain.One of the possible mechanisms of infrared radiant ceramic belts is related to the infrared thermal effects which radiated from ceramic stones (natural minerals are infrared radiant) [The other possible mechanism is that infrared is effective in inhibiting prostaglandin production and has anti-inflammatory and analgesic effects. Also, infrared ceramic materials exert an antioxidant effect by increasing the degradability of hydrogen peroxide, which consequently, reduces ischemia and pain [Another point is that, infrared radiation increases calcium-dependent nitric oxide (NO) [Also the biological and physiological effects of infrared are not only related to heat but also to the main types of light receptors(i.e., cytochrome oxidase and intracellular water), in other word infrared has thermal and radiant effect as well [Yaghoubi et al. (2012) conducted a study to compare the effect of infrared and hot water bag on lumbar disc herniation pain represented that the pain intensity was decreased equally in both groups [The results of the present study showed no difference in the 1- and 5-min Apgar scores between the intervention and control groups. In Akbarzadeh et al. (2017) study, there was no difference between the hot compress group and the routine group regarding the 1- and 5-min Apgar scores as well [The results of the present study showed that there was a significant difference between the two intervention groups in terms of satisfaction and infrared belt had greater effect in this regard. In Taavoni et al. (2013) study the mean score of satisfaction was significantly higher in the heat therapy group than in the control group as well [It has been reported when women's expectations of childbirth are met, their satisfaction would be increases. Some of the aspect of labor like relieving pain and reducing labor length is related to women`s satisfaction. The greater satisfaction after intervention with the infrared belt can be explained by the greater effectiveness, reduced labor length and ease of use [As a strength of our study, it is worthwhile to mention that this study is the first clinical trial which investigate the effect of infrared belt as a new non pharmacologic method on the management of labor pain. This random allocation study was performed on three groups which compare the effect of infrared belt with hot water bag on the labor pain intensity. Women’s difference in the pain tolerance and other characteristic like their cognitive attributes can be affected on their pain response, which was controlled by random allocation. Moreover, environmental conditions, could be influenced the pain intensity of women, which was the same in all groups (similar sampling environment).