The impact of omega-3 polyunsaturated fatty acids on primary dysmenorrhea: a systematic review and meta-analysis of randomized controlled trials

Background Primary dysmenorrhea is one of the most common complaints in women. To date, no definitive results have been reported on the effect of omega-3 polyunsaturated fatty acids (n-3 PUFAs) on primary dysmenorrhea. Therefore, this study aimed to determine the effect of n-3 PUFAs on primary dysmenorrhea using a systematic review and meta-analysis. Methods This study is a systematic review and meta-analysis in which the electronic databases of PubMed, Scopus, Web of Science, ProQuest, Google Scholar, and SID were searched. In this regard, randomized controlled trials (RCTs) conducted to investigate the effect of n-3 PUFAs on primary dysmenorrhea were included. The quality of the studies was assessed using the Cochrane Collaboration's Risk of Bias Tool. Meta-analysis was performed based on the random-effects model using CMA software version 2. Results The results of the meta-analysis showed that n-3 PUFAs reduce the severity of primary dysmenorrhea in women (SMD = -1.075, 95% CI: -1.871 to -0.279); meta-regression showed that the daily intake of n-3 PUFAs (beta = 0.005, 95% CI 0.003 to 0.008, p < 0.001) and age of women (beta = 0.256, 95% CI -0.157 to -0.354, p < 0.001) had a significant effect on the severity of primary dysmenorrhea. Conclusion The present study showed that n-3 PUFAs could have a mild effect on the severity of primary dysmenorrhea in women. Furthermore, the highest effectiveness of treatment was seen at low doses of n-3 PUFAs, and with increasing daily intake, the effectiveness of treatment with n-3 PUFAs decreased. Another finding indicated that with the increasing age of women, n-3 PUFAs showed lesser effectiveness in reducing the severity of primary dysmenorrhea. The results of the present study provide valuable evidence to primary healthcare providers and health policymakers in the treatment of primary dysmenorrhea.