Primary dysmenorrhea (PD), also known as functional dysmenorrhea, that is the menstrual cramps with no apparent organic lesions. Its typical symptoms are characteristic by crampy, colicky spams of pain during menstruation, and regularly coupling with dizziness, sickness, emesis, diarrhoea, and fatigue, even cold limbs, syncope and other severe symptoms. In some case, this situation bring much pain to the patients.
PD are common affliction among women, whose prevalence is relatively high among adolescent and young adult females. The previous study has reported that the PD prevalence in global women was 25%, while was 90% in global teenagers and approaching 15% of patients feeling in great pain[2, 3]. A recent study in Japan has shown that the morbidity of dysmenorrhea varies with age, wherein 12 years old, its ratio was 31.6%, 13 years old was 39.5%, 14 years old was 50.3%. In China, the morbidity of dysmenorrhea accounts for 33.1%, that more than half is primary dysmenorrhea, greatly affecting patients both physically and mentally.
The reason for PD is related to many factors, and the pathogenesis not yet fully elucidated. It has been proved that PD was associated with the hypercontractility of uterine smooth muscle and spiral artery of uterine wall, so that inducing ischemia and hypoxia and triggering pain in the hypogastrium[6, 7]. Recently years, many studies have defined the over synthesis of prostaglandin in the endometrium as the dominant reason for PD, especially the PGF2α and PGF2 that play a fundamental role in increasing uterine muscle tone and high-intensity contraction, triggering the acid metabolites adding up in the myometrium thus causing pain[8–11]. Otherwise, some studies suggests that ET and NO are also important factors causing primary dysmenorrhea, those mainly regulates uterine vascular tone and blood flow.
For the treatment of PD, the currently recommended pharmacological therapies of PD mainly included nonsteroidal anti-inflammatory drugs, prostaglandin antagonists, oral contraceptives and anti-spasmodic drugs. To some extent, these medications can temporarily alleviate pain, but it is associated with some shortcoming, such as high recurrence rate, drug resistance, particularly when used for the long term, which is easy to produce gastrointestinal discomforts, and long haul renal dysfunction[13, 14]. Therefore, seeking complementary and alternative treatment for PD to relieve pain is significant. Traditional Chinese medicine described that primary dysmenorrhea is closely related to "stasis", "stagnation" and "deficiency", and should be treated by the principle of warming yang for dispelling cold, activating blood circulation, and unblocking collaterals.
Moxibustion, as an external therapy of traditional Chinese Medicine, has a wide range of applications to prevent and treat diseases with the advantages of simple operation and good economic benefits. As we all know, the warm and hot stimulation of moxibustion can warm the meridians and activate the collaterals and keep the Qi and blood running unobstructed to relieve the pain symptoms. Modern studies have confirmed that moxibustion can redistribute microcirculatory blood flow in the body by affecting the function of microvascular relaxation and contraction. Another study has shown that moxibustion can significantly reduce the levels of PGF2ɑ and PGF2ɑ / PGE2 in uterine tissues of Dysmenorrhea Rats, and improve the activity of NK cells in the spleen of rats[17–18].
Although plenty of studies have reported the curative effect and safety of moxibustion for PD, there is still a lack of guidelines involving moxibustion for PD, so we need to formulate relevant clinical practice guideline (CPG). Moreover we preliminary found more than 200 RCTs as well as some SRs or meta-analysis using moxibustion to treat PD, all that have been regarded as the basis of drawing up CPG.