In this study, the heat wrap group had milder pain during the first 24 hours of menstruation compared with the ibuprofen group, but this difference was not statistically significant.
Increased attention has recently been paid to non-pharmacological treatments for dysmenorrhea [25, 26]. However, only a few studies have addressed this issue. Akin and colleagues showed that local heat was as effective as ibuprofen for the treatment of dysmenorrhea [16, 27]. However, local heat was not shown to be effective in other reports . A new thermogenic device has also been evaluated which provides a constant temperature of 40 °C for 8 hours through the oxidation of iron chips, which does not interfere with daily activities and is effective, safe, and reasonably priced .
In our study, pain was measured using the SF-MPQ. This questionnaire has three main sections and contains a number of phrases to assess the individual’s pain perception (sensual and emotional). Cultural differences, socioeconomic factors, the availability of support, and the individual’s personality play an important role in pain perception. The McGill questionnaire takes these into consideration. Bajaj and colleagues also used this tool to compare the effects of local heat on the pain threshold of women with and without dysmenorrhea and found that dysmenorrhea pain could be soothed by applying local heat, and that pressure on the abdomen and back increased the pain threshold . In our study, we applied heat to only one point. We found that the total pain rating was less in the local heat group, although there were no significant differences between groups.
There were noticeable differences in the emotional aspects of pain during the first 12 hours after the onset of menstruation, but these were not statistically significant. In this the current pain score appears was low in Ibuprofen group than in heat patch group at 8 h, because the maximum effectiveness pad is 8 hours. But This difference was not significant (t = 1.18, p = 0.24). With a larger sample size, this difference may have become significant. Akin and colleagues compared the effectiveness of oral ibuprofen or placebo with and without local heat, and observed that ibuprofen with and without local heat was more effective than placebo. Local heat (non-thermal wrap) was also found to be more effective than placebo. The analgesic effect was significantly faster in the ibuprofen plus local heat group than in the other groups .
There are some notable differences between our study and that by Akin and colleagues. We used an 84 cm2 patch and the multidimensional McGill pain score tool, and Akin used a 180 cm2 wrap and a one-dimensional visual analog pain scale, but these differences should not affect the results. Both studies applied local heat to the same area of the abdomen.
Some of our results are consistent with those of Bajaj and colleagues, who reported that a towel containing an iron chip was more effective in reducing back pain than ibuprofen and acetaminophen on the first, third, and fourth days of menstruation, which was probably due to the large surface area of application and to the area where the heat was applied. This effect could be due to pressure-sensitive points on the back. In comparison with acetaminophen, these towels have been shown to be more effective in the treatment of dysmenorrhea at 3, 4, 5, and 6 hours after the onset of menstruation . Some studies have shown that transcutaneous electrical nerve simulation, which works by the same mechanism as local heat, can be effective for the treatment of dysmenorrhea. This method places stimulatory electrodes over the lumbar and sacral areas, together with local heat. Further investigation of this method is needed . Heat wraps have also been compared with acetaminophen, and were found to be significantly more effective .
Although pharmacotherapy can be used to treat dysmenorrhea, it is not effective in 20–25% of patients . Using NSAID drugs as first-line treatment may be limited because of adverse reactions such as gastrointestinal side effects, which mandates the selection of alternative therapeutic modalities.
A retrospective study of the complications of dysmenorrhea showed that 98% of teenagers had used one or more methods to control the pain . In another study, all participants had used local heat to treat the pain . The physiological effects of thermal therapy act via nervous, vascular, and biophysical pathways. Analgesia via the nervous pathway can be explained by Melzack's gate-control theory of pain. [25, 26]. This theory provides a logical explanation for the use of pain control measures such as local heat, cold, pressure, massage, and electrical stimulation . These findings are compatible with the findings of Akin and Nadler [16, 27, 28].
Heat induced vascular reactions will increase the blood flow to an area, resulting in the dilution of intravascular prostaglandins, bradykinin, and histamine. These molecules are among the most potent pain inducing molecules. Increased blood flow also improves tissue oxygenation . Local heat applied to the upper abdomen increases gastrointestinal motility and has a relaxing effect on the uterus. Previous studies have provided explanations for this mechanism . NSIADs are the standard medications used to treat dysmenorrhea. Local heat is as effective as NSIADs , but users should be aware of potential side effects of NSAIDs.
Few studies have addressed the use of ibuprofen for dysmenorrhea in Iran [33–35]. Our study is the first which compares the effectiveness of this medication with local heat. There are some studies from other countries which evaluate NSAIDs for the treatment of dysmenorrhea, but according to a review study, there is little or no evidence regarding the safety and adverse effects of these drugs . We found that this apparently insignificant result could open a new scenario for women who can’t be treated by FANS (e.g. allergy, haemorrhagic diathesis, gastric ulcera).
Our study has some limitations, including the effects of variations in the thickness of lower abdominal adipose tissue which acts as a thermal insulator  However, abdominal circumference and BMI were similar between groups. Blinded, double blinded, or triple blinded treatments were not possible in our study since the therapeutic measures used were obvious. The pain threshold varied among subjects, because people experience pain differently in different emotional states, which was beyond the control of the investigators. We excluded women with a history of psychiatric or personality disorders and those who were grieving to address this issue.