The Effect of Ginger, Cinnamon, and Fennel on Primary Dysmenorrhea: A Systematic Review and Meta-Analysis

Introduction: Primary dysmenorrhea (PD) is a common problem among young women. In addition to chemical drugs, herbal medicines have also been used as pain relievers for PD. Methods: In this systematic review and meta-analysis, a query was conducted on databases including Cochrane, Web of Science, PubMed, SID, Magiran, IranDoc, and the Google Scholar search engine until February 5, 2023. All studies utilized the Visual Analogue Scale (VAS). STATA 14 software was used for statistical analysis, and the significance level of the tests was considered P < 0.05. Results: In 18 studies with a sample size of 1,372 people, the results based on the VAS tool demonstrated that before the intervention, there was no significant difference between the intervention group (cinnamon, ginger, or fennel) and the control group in terms of pain severity and duration. Nonetheless, after the intervention, the pain severity was less severe in the ginger group than in the control group [standardized mean difference (SMD) = -1.03 (95% CI: -1.66, -0.41), P = 0.000]. The ginger and control groups did not differ in pain duration [SMD = -0.26 (95% CI: -0.56, 0.04), P = 0.319]. There was no significant difference in pain intensity in the fennel group compared to the control group [SMD = -0.13 (95% CI: -0.75, 0.48), P < 0.001]. There was no significant difference between the cinnamon and control groups regarding pain intensity [SMD = -1.71 (95% CI: -4.64, 1.21), P < 0.001]. Moreover, pain duration did not differ in the cinnamon and control groups [SMD = -15.40 (95% CI: -35.33, 4.53), P < 0.001]. Conclusions: As evidenced by the obtained results, the consumption of ginger reduced the intensity and duration of pain caused by PD. Nonetheless, further studies need to be performed on fennel and cinnamon.