Acupuncture for clinical improvement of endometriosis-related pain: a systematic review and meta-analysis

Endometriosis is a common chronic gynecological condition characterized by the presence of endometrial tissue outside the uterine cavity, leading to chronic inflammation, pelvic nodules and masses, pelvic pain, and infertility. Acupuncture has been shown to improve pain associated with endometriosis by modulating abnormal levels of prostaglandins, β-endorphins, dynorphins, electrolytes, and substance P. This review aims to evaluate the clinical efficacy of acupuncture in treating endometriosis, specifically focusing on its efficacy in relieving pain associated with endometriosis. A comprehensive search was conducted in eight databases (PubMed, EMBASE, Cochrane, Web of Science, China National Knowledge Infrastructure (CNKI), the China Biology Medicine (CBM), Wanfang, and Weipu database) to identify randomized controlled trials (RCTs) published from database inception to December 16, 2022, which investigated the use of acupuncture for endometriosis-related pain. Two researchers independently screened articles, extracted data, and assessed methodological quality using the Cochrane Collaboration's risk of bias tool. Meta-analysis was performed using Stata statistical software. A total of 1991 articles were identified, and ultimately, 14 studies involving 793 patients (387 in the acupuncture group and 359 in the control group) were included. The control interventions in the included studies included placebo, traditional Chinese medicine (TCM), and Western medicine treatments. Meta-analysis results showed that compared to the control group, acupuncture treatment for pain associated with endometriosis demonstrated significant reductions in pain severity [SMD = − 1.10, 95% CI (− 1.45, − 0.75), P < 0.001], improved response rate [RR = 1.25, 95% CI (1.09, 1.44), P = 0.02], and decreased serum CA-125 levels [SMD = − 0.62, 95% CI (− 1.15, − 0.08), P = 0.024]. Furthermore, subgroup analysis revealed that electroacupuncture and auricular acupuncture were superior to the control group in reducing pain severity, while auricular acupuncture and warm needling showed greater clinical efficacy compared to the control group. However, there were no significant differences between electroacupuncture or fire needling and the control group in terms of pain relief. The findings suggest that acupuncture is effective in improving pain associated with endometriosis. In conclusion, acupuncture is effective in alleviating dysmenorrhea and pelvic pain associated with endometriosis, reducing serum CA-125 levels, decreasing the size of nodules, improving patients' quality of life, and lowering the recurrence rate. However, it should be noted that the current evidence is limited by the design and quality flaws of the original studies, as well as a lack of research specifically focusing on subtypes of acupuncture. Therefore, caution should be exercised when interpreting the results.