Background
neuropathic pain, hyperalgesia, labor pain, spasm, inflammation, decreases laminar shear stress, excruciating, pain, tissue stiffness, Labor pain, labor, musculoskeletal pain, dysmenorrhea
INFLAMMATION, PRIMARY DYSMENORRHEA, DYSMENORRHEA, HEAT, OXIDATIVE STRESS, COLD
The labor and its related pain are a unique experience for every parturient woman. The majority of women experience pain during childbirth as a normal physiological aspect of this process. Labor pain is complex and paradoxical which is different and diverse in women. Generally, every woman experiences it in different ways from excruciating to a pleasure [In this regard pharmacological and non-pharmacological methods can be applied to relieve labor pain. Pharmacological methods for pain relief include; Inhaled analgesia, Opioid and Non-opioid drugs, Local anesthesia and Epidural [Among this method, physical therapy involves the use of heat, cold, hydrotherapy, manipulation, and electric currents. Heat therapy is one of the most common methods used in physical therapy [Heat causes the blood vessels to dilate and increases the blood flow, which will lead to a growth in the volume of cell exchange. Stimulation of heat receptors, based on the pain gate mechanism, closes the pain transfer valves, controls the entry of pain impulses into the nerve pathways, consequently, reduces the pain [Silicone hot water bags, which heat the under-treatment area and increase the blood circulation in that region are used to reduce spasm, pain, and soft tissue stiffness [Another method of heat therapy is using IR [It was reported that infrared radiation absorption activates signaling pathways involved in pain perception. Potential explanations for how infrared therapy might relieve musculoskeletal pain include increased nitric oxide (NO) levels, decreased oxidative stress, and the induction of inflammatory mediators [Through local processes, oxidative stress may change nociception and result in hyperalgesia. Reactive oxygen species produced as a result of oxidative stress damage tissues and induce inflammation, which in turn stimulates sensory neurons that are involved in the transmission of pain more intensely. Infrared therapy has the potential to reduce pain and inflammation in the muscles by lowering the degree of oxidative stress [Numerous investigations have shown that the biological effects of infrared irradiation are connected to the NO pathway. Vasodilation, which decreases laminar shear stress, is one of the short-term effects of infrared irradiation. It has been demonstrated that NO has a role in peripheral inflammatory and neuropathic pain. The activation of ATP-sensitive K + channels in the membrane of nociceptors, is one proposed mechanism of action of NO as a peripheral antinociceptive agent [Some studies revealed that electrically and noxiously elicited action potentials, including pro-inflammatory mediators, were inhibited by infrared light. Microtubule array disruption and rapid axonal flow may support neuronal inhibition [To the best of our knowledge, no specific research has been conducted to investigate the effect of infrared belt on labor pain. However, some studies have been performed evaluating the effect of IR on pain relief of primary dysmenorrhea. In this regard, Yi Liau et al. (2011) and Lee et al. (2009) showed that infrared belt can be used as an appropriate and effective way for the treatment the symptoms and relief of dysmenorrhea [Exposure to infrared radiation is not dangerous and poses no significant risk, because, infrared photons are not powerful enough to produce ionizing radiation [To the best of our knowledge, no particular research has been carried out comparing infrared belt with hot water bags in labor pain relief. Therefore, this study was designed and conducted to evaluate the effect of the infrared belt and the hot water bag on the severity of labor pain in primiparous women and report the possible side effects of these methods.