Primary dysmenorrhea is defined as cramping pain in the lower abdomen occurring just before or during menstruation, in the absence of other diseases such as endometriosis.(1) Prevalence rates are as high as 90 percent. Women with primary dysmenorrhea have increased production of endometrial prostaglandin, resulting in increased uterine tone and stronger, more frequent uterine contractions.(1) Nonsteroidal anti-inflammatory medications are the mainstay of treatment, with the addition of oral contraceptive pills when necessary. About 10 percent of affected women do not respond to these measures.(1)
Acupoint injection has been evaluated for the treatment of primary dysmenorrhea with promising results. In traditional Chinese medicine (TCM), the acupuncture point SP-6 (Spleen-6, Chinese Name: SanYinJiao, English Name: Three Yin Intersection) is a place where the three yin meridians (Spleen, Liver and Kidney) of the foot cross over each other.(2) Menstruation is attributed to these three meridians in TCM and when there is an issue with menstruation, it is these systems that are evaluated first in TCM.
Several TCM text books describe SP-6 as an effective point for treating dysmenorrhea from a TCM perspective. From a Western perspective, it has been hypothesized that stimulation of SP-6 may have an effect on prostaglandin levels, but this has not been shown in research studies.(3) A meta-analysis comparing acupuncture at SP-6 to a control point (GB-39) did not find statistically significant differences between the two points.(4) In contrast, a large research study published in 2014 with over 500 participants was able to detect a statistically significant difference in favour of acupuncture at SP-6 compared to GB-39 and a non-acupoint for pain ratings using the visual analog scale.(5) The other outcomes that were measured such as symptom scales did not show a difference, leading the researchers to conclude;
Specific acupoint acupuncture produced a statistically, but not clinically, significant effect compared with unrelated acupoint and nonacupoint acupuncture in primary dysmenorrhea patients.
Part of what makes acupuncture so hard to study is that comparing active treatments to each other makes it very difficult to detect a difference between groups unless the sample size is very large. In the aforemention study of 500 participants, the results looked like they were trending towards a more pronounced benefit for acupuncture at SP-6, however this could not be demonstrated.
Acupoint injection, because it is a combination between needle effects and that of different medicines, may provide a strong enough effect that differences can be detected with smaller sample sizes as shown in the following studies.
A 2014 study compared acupoint injection of Vitamin K3 in to SP-6 (4mg per side) along with massage of SP-8 to oral administration of Ibuprofen sustained-release capsule.(6) After treatment, pain scores were obviously decreased in both groups and the differences were statistically significant. The difference in pain score after treatment was more significant in the treatment group than that in the control group. The total effective rate was significantly higher in the treatment group than that in the control group.
These results were confirmed in 2015 in a randomized cross-over pilot study done in the United States study comparing acupoint injection of Vitamin K1 in to SP-6 or saline in to a non-acupoint for primary dysmenorrhea.(7) Women had an average 2.5 point decrease in pain after vitamin K1 injection in Spleen-6 compared with a 1.8 point decrease after saline. Change scores of vitamin K1 compared with saline injection approached statistical significance. The small sample size of 16 participants may have contributed to an inability to detect a large enough difference between the two groups.
Finally in a 2016 study that had 80 participants, was double blinded, and two groups were controls groups with one active group compared acupoint injection of vitamin k3 in SP-6 (group C) to saline in SP-6 with vitamin k3 in the buttocks (group B), or saline in a non-acupoint (group A).(8) This was to see if it was the vitamin k3 alone causing the improvement, or if it was the vitamin k3 in SP-6. When treated with an acupoint injection of vitamin K3 in SP6 participants had an average 6.6 point decrease in pain within 60 min after injection. The average pain decreased by 4.9 points in the saline acupoint injection group (group A) and 4.7 points in the vitamin K3 buttock injection group (group B).
Acupoint Injection of Vitamin K into SP-6 does appear to be the most effective treatment available for primary dysmennorhea for those that have it as an option, however it's clear from the research that any stimulation through needles and even saline can provide a clinically important effect providing relief for patients. It may also be beneficial to do trigger point injections on the abdominal muscles as a preventative for primary dysmennorhea, which has shown promising results as well.(9)
- Coco Andrew S. ― "Primary Dysmenorrhea" in Am Fam Physician. 1999 Aug 1;60(2):489-496. http://www.aafp.org/afp/1999/0801/p489.html
- Acupuncture.com - Spleen 6.
- Shi GX. Effects of acupuncture at Sanyinjiao (SP6) on prostaglandin levels in primary dysmenorrhea patients. Clin J Pain. 2011 Mar-Apr;27(3):258-61. http://www.ncbi.nlm.nih.gov/pubmed/21358291
- Chen MN. "Acupuncture or Acupressure at the Sanyinjiao (SP6) Acupoint for the Treatment of Primary Dysmenorrhea: A Meta-Analysis" in Evid Based Complement Alternat Med. 2013;2013:493038. http://www.ncbi.nlm.nih.gov/pubmed/23533489
- Liu CZ. "A randomized controlled trial of single point acupuncture in primary dysmenorrhea." in Pain Med. 2014 Jun;15(6):910-20. http://www.ncbi.nlm.nih.gov/pubmed/24636695
- Li-xia, Lü. ― Observation on the Effect of Acupoint Injection plus Massage Therapy on Primary Dysmenorrhea in Journal of Acupuncture and Tuina Science 12, Issue 4 (July 2014), pp. 256-259. http://link.springer.com/article/10.1007/s11726-014-0784-8
- Chao, MT. ― An innovative acupuncture treatment for primary dysmenorrhea: a randomized cross-over pilot study in Alternative Therapies, Health and Medicine 20, Issue 1 (January 2014), pp. 49–56. Accessed December 28, 2015 at http://www.ncbi.nlm.nih.gov/pubmed/24445356
- Wade C. "Acupuncture point injection treatment of primary dysmenorrhoea: a randomised, double blind, controlled study" in BMJ Open. 2016; 6(1): e008166. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4716272/
- Qiang-Min, Huang. ― Wet needling of myofascial trigger points in abdominal muscles for treatment of primary dysmenorrhoea in Acupuncture in Medicine 32, Issue 4 (May 2014), pp. 346-349. Accessed December 28, 2015 at http://aim.bmj.com/content/32/4/346.abstract