Chinese Herbal Medicine, Alternative or Complementary, for Endometriosis-Associated Pain: A Meta-Analysis

Current medical treatments for endometriosis-associated pain (EAP) have limitations, including symptom recurrence and hormonal side effects. For this reason, it is important to elucidate any alternative or complementary treatments available, while Chinese herbal medicine (CHM) shows potential to be this treatment. This study aims to provide evidence for the efficacy and safety of CHM for EAP. Randomized control trials comparing CHM to other treatments for EAP in women with endometriosis were considered eligible, and they were searched for in Medline, Embase, Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov, as well as in the Chinese databases Sino-Med and CNKI, from inception to October 2021. Numerous outcomes were put through meta-analysis using a weighted mean difference and a 95% CI, and the results of dichotomous data were presented as a pooled RR with a 95% CI. A total of 34 eligible studies with 3389 participants were included. Compared with no treatment, there was a statistically significant pooled benefit of CHM on dysmenorrhea at the end of 3-month treatment, and these effects continued for 3 months, but not 9 months, after treatment. Compared with conventional therapy, a significant difference was found in the levels of pelvic pain with a lower rate of hot flush and irregular vaginal bleeding at the end of treatment for 3 months, but not after treatment. Comparing combined treatment with CHM and conventional therapy with conventional therapy alone, significant decreases were found in dysmenorrhea, dyspareunia, and pelvic pain after a 3-month treatment cycle, and in dysmenorrhea after a 4-month treatment cycle with a lower hot flash rate. In conclusion, CHM, used alone or in combination with conventional therapies, appears to have benefits in relieving EAP with fewer side effects than traditional treatment.