Efficacy of acupuncture for endometriosis-associated pain: a multicenter randomized single-blind placebo-controlled trial

This multicenter randomized placebo-controlled clinical trial investigated the efficacy of traditional Chinese acupuncture in the treatment of endometriosis-associated pain, a gynecologic condition that affects approximately 10% of women of reproductive age. Endometriosis is characterized by the growth of endometrial tissue outside the uterine cavity, causing chronic pain, infertility, and pelvic masses; 70% to 90% of women with this condition experience chronic pain that significantly affects their quality of life. The study was conducted at four tertiary hospitals in the provinces of Jiangxi and Hainan, China, between March 2018 and November 2021. Of 566 women assessed, 106 were randomized to receive true or sham (placebo) acupuncture.

Inclusion criteria included age between 20 and 40 years, regular menstrual cycles, confirmed diagnosis of endometriosis, and a history of maximum pain ≥4 points on the visual analog scale (VAS). The treatment protocol consisted of 30-minute sessions, once daily, three times per week for 12 weeks, beginning one week before expected menstruation. The acupuncture group received needling at specific points including Guanyuan (CV-4) and bilateral points Sanyinjiao (SP-6), Taichong (LR-3), Zhaohai (KI-6), and Qichong (ST-30), totaling 9 needles inserted to a depth of 15-35 mm with manual stimulation to obtain De Qi. The control group received superficial needling (<5 mm) at non-points on the shoulder and arm without stimulation.

Primary outcomes showed that acupuncture significantly reduced dysmenorrhea at week 12, with the acupuncture group showing a reduction of 3.9 points on the VAS compared with 1.0 point in the sham group (difference of -2.9 points, p < 0.0001). Total duration of pelvic pain was also significantly lower in the acupuncture group (13.8 vs. 19.2 hours, p = 0.003). In addition, the acupuncture group showed significant improvements on all secondary measures at week 12, including physical function (MPI), emotional state (BDI and POMS), and quality of life (EHP).

However, the benefits did not persist at the week-24 follow-up assessment, suggesting that the effects of acupuncture are temporary and require ongoing treatment. No significant differences were observed in non-menstrual pelvic pain or dyspareunia between groups, possibly because of low baseline scores for these symptoms. The safety profile was excellent, with only three minor adverse events (subcutaneous hemorrhage at the needle site) that did not require medical intervention. The study has several methodological strengths, including multicenter design, adequate randomization, blinding of participants and assessors, and intention-to-treat analysis.

Limitations include the inability to blind the acupuncturists, the primary focus on moderate-to-severe dysmenorrhea, and possible reduced generalizability due to strict inclusion criteria.