Clinical Evidence of Acupoint Stimulation for Primary Dysmenorrhea: A Systematic Review and Updated Meta-Analysis.

PURPOSE

Meridian-based acupoint stimulation is increasingly used for primary dysmenorrhea (PD), yet its evidence remains inconsistent. This systematic review aims to evaluate efficacy and safety of both invasive and noninvasive acupoint stimulation for PD through analysis of randomized controlled trials (RCTs).

METHODS

The PROSPERO registration number is CRD42024586857. PubMed, Excerpta Medica Database (Embase), Allied and Complementary Medicine Database (AMED), Cochrane Central Register of Controlled Trials (CENTRAL), Web of Science, Scopus, VIP Database, China National Knowledge Infrastructure (CNKI), and Wanfang Database were searched up to May 20, 2024. Methodological quality was assessed using the revised Cochrane risk of bias, version 2 tool. Data were synthesized using random-effects models and presented with forest plots. The primary outcomes were assessed based on pain intensity measured using the Visual Analog Scale (VAS) or effective rates, and safety measured by adverse reaction rates. The secondary outcomes included self-reported symptoms and quality of life, uterine hemodynamics, and serum prostaglandin contents.

RESULTS

A total of 22 eligible RCTs with 1955 participants (range 44 to 216) were included. Compared with no treatment or sham treatment, acupoint stimulation demonstrated moderate pain reduction (standardized mean difference [SMD] -2.96, 95% confidence interval [CI] -4.39 to -1.53). Compared with non-steroidal anti-inflammatory drugs (NSAIDs), acupoint stimulation showed both immediate effects (post-first-treatment SMD -2.85, 95% CI -4.06 to -1.64) and sustained benefits (3 cycles SMD -1.58, 95% CI -2.43 to -0.73; following 3 cycles SMD -3.74, 95% CI -5.57 to -1.90), particularly with invasive techniques. The incidence of adverse events did not differ significantly between groups (relative risk [RR] 0.94, 95% CI 0.26 to 3.33). The GRADE certainty of the evidence ranged from low to moderate, owing to considerable risk of bias and high heterogeneity.

CONCLUSION

Current evidence suggests that acupoint stimulation may reduce pain intensity in primary dysmenorrhea without increasing adverse reactions, particularly long-term.