Effectiveness and safety of Chinese medicine at Shenque (CV 8) for primary Dysmenorrhea: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND: Primary dysmenorrhea (PD) is the most common complaint associated with menstruation and affects up to three-quarters of women at some stage of their reproductive life. In Chinese medicine, navel therapy, treatment provided at Shenque (CV 8), is used as a treatment option for PD.OBJECTIVE: To evaluate the effect of navel therapy on pain relief and quality of life in women with PD, compared with Western medicine (WM).METHODS: China National Knowledge Infrastructure (CNKI), Chinese Scientific Journal Database (VIP), SinoMed and Wanfang Database, MEDLINE, the Cochrane Library, Embase, Web of Science, and the International Clinical Trial Registry of the U.S. National Institutes of Health were searched from their inceptions to April 1, 2021. Randomized controlled trials (RCTs) assessing therapeutic effects of navel therapy on PD were eligible for inclusion. RevMan 5.4 software was used for data analyses. The certainty of the evidence was assessed using the online GRADEpro tool.RESULTS: Totally 24 RCTs involving 2,614 participants were identified. Interventions applied to acupuncture point CV 8 included: herbal patching, moxibustion or combined navel therapy (using at least 2 types of stimulation). Compared to placebo, there was a significant effect in favor of navel therapy on reducing overall menstrual symptom scores at the end of treatment [mean difference: -0.82, 95% confidence interval (CI): -1.00 to -0.64, n=90; 1 RCT]. As compared with Western medicine, navel therapy had a superior effect on pain intensity as assessed by Visual Analogue Scale at the end of treatment [standardized mean difference (SMD): -0.64, 95% CI: -1.22 to -0.06, I2=80%, n=262; 3 RCTs]; on symptom resolution rate at 3-month follow-up (risk ratio: 1.94, 95% CI: 1.47 to 2.56, n=1527, I2=38%; 13 RCTs); and on global menstrual symptoms score at the end of treatment (SMD: -0.67, 95% CI: -0.90 to -0.45, I2=63%, n=990; 12 RCTs). Subgroup analyses showed either a better or an equivalent effect comparing navel therapy with Western medicine. No major adverse events were reported. The methodological quality of included trials was poor overall.CONCLUSIONS: Navel therapy appears to be more effective than Western medicine in decreasing menstrual pain and improving overall symptoms of PD. However, these findings need to be confirmed by well-designed clinical trials with adequate sample size (Systematic review registration at PROSPERO, No. CRD42021240350).