The effects of Vitex agnus-castus on menstrual bleeding: A systematic review and meta-analysis

Introduction Vitex agnus-castus, also called Vitex, is a plant with many medicinal properties. This systematic study examined the evidence of the effectiveness and safety of Vitex on menstrual bleeding (primary outcome) and its side effects (secondary outcomes). Materials and methods This systematic review study examined all papers that were a randomized controlled trial, quasi-experimental, and cross-over conducted on the effect of Vitex on menstrual bleeding, following the PICO (population, intervention, control, and outcomes) criteria without any time limits in December 2017. The participants were women of reproductive age with no gynecologic disorders. The intervention included the use of Vitex in form of tablets, capsule, or oral drops with different doses. The control group included the placebo or mefenamic acid group. The search strategy in this study was in accordance with MeSH terms. The keywords used separately or in combination with other words were Menstrual bleeding OR Menstruation OR Menorrhagia AND Vitexcastus OR Vitex OR Chasteberry AND randomized controlled trial OR randomized trial OR randomized clinical trial OR randomized controlled. All papers, including Persian or English, were searched for in the databases; Medline (through PubMed), Scopus, Embase (through Ovid), Cochrane Library, Web of Sciences, Google Scholar, SID, Magiran, Irandoc, and Iranmedex, without any time limits. Two authors independently reviewed the quality of the papers and assessed the risk of bias based on Cochrane handbook, and the disputes were resolved through discussion and consensus with a third person. The meta-analysis was done on continuous data (mean of menstrual bleeding). In meta-analysis, subgroup analysis was performed based on the type of comparison group. Results Out of the 8,905 searched papers in the databases, 8,905 titles, 720 abstracts, 85 full texts, and 20 references of the papers were reviewed, of which 5 papers entered this study. Based on the subgroup analysis, the consumption of Vitex did not have a significant effect on the amount of menstrual bleeding compared to the placebo group in the first (mean difference [MD]: 3.08; 95% CI: -3.11-9.26; p=0.33; I2=0%) and second menstrual cycles (MD: 0.00; 95% CI: -5.75-5.75; p=1.00; I2=0%). Also, the Higham mean score was statistically more in the Vitex group compared to the mefenamic acid group in the first menstrual cycle (MD: 7.17; 95% CI: 0.33-14.01; p=0.04; I2=0%) but there was no statistical significant difference between Vitex and mefenamic acid groups in the second menstrual cycle (MD: 12.18; 95% CI: -5.57-29.94; p=0.18; I2=75%). Only nausea and abdominal pain were reported as side effects of Vitex in the included studies. Conclusions The results of this study showed that the consumption of Vitex in the intervention group did not have a significant effect on menstrual bleeding in comparison with the placebo group. However, due to the relatively low quality of the papers, it is essential to perform clinical trials with an appropriate design to determine the effect of Vitex on menstrual bleeding.