Abstract
Fennel is used as an alternative treatment for primary dysmenorrhea. This review aims to evaluate the effectiveness and safety of fennel for reducing pain in primary dysmenorrhea. Twenty databases, including English, Korean, Chinese, Japanese, Iranian, and Spanish databases, were searched from inception to 20 October 2020. All randomized controlled trials (RCTs) investigating the effectiveness of fennel for treating primary dysmenorrhea were considered. Two reviewers conducted the data extraction and risk of bias assessment independently. Any discrepancies were resolved through discussion with a third reviewer. A total of 12 studies were included in this review. The pooled results of seven trials showed that the effect of fennel is similar to that of conventional drug therapies in alleviating pain (n = 502, standardized mean difference (SMD): 0.07, 95% confidence interval(CI): −0.08 to 0.21, p < 0.37, I2 = 0%). In comparison with placebo, fennel was seen to have favorable effects on reducing pain in primary dysmenorrhea (n = 468, SMD: −3.27, 95% CI: −5.28 to −1.26, p = 0.001, I2 = 98%). Only three studies assessed adverse events (AEs), and one study reported minor AEs. Although the risk of bias for all the included studies was moderate, potential publication bias was observed due to the presence of a greater number of small studies with favorable effects. This systematic review concludes that fennel is as effective as conventional drug therapies in alleviating pain in primary dysmenorrhea. More studies that include more diverse populations and robust evidence of fennel’s effects will be needed in future research endeavors.
Highlights
Primary dysmenorrhea, commonly known as menstrual cramps, is a recurrent pain around the lower abdomen occurring immediately before or during menstruation in the absence of underlying conditions, and it is often accompanied by symptoms such as fatigue, headaches, dizziness, nausea, sweating, and diarrhea [1]
We identified 1039 potentially relevant of which metRCTs our inclusion
We identified 12 randomized controlled trials (RCTs) that addressed the effects of fennel on reducing pain in primary dysmenorrhea
Summary
Commonly known as menstrual cramps, is a recurrent pain around the lower abdomen occurring immediately before or during menstruation in the absence of underlying conditions, and it is often accompanied by symptoms such as fatigue, headaches, dizziness, nausea, sweating, and diarrhea [1]. It is a common gynecological condition, and approximately 45 to 95% of menstruating women suffer from it [2]. Nonsteroidal anti-inflammatory drugs (NSAIDs) such as mefenamic acid are the first-line pharmacological treatments for dysmenorrhea [1]. One of the complementary medicines widely used for dysmenorrhea, are considered supplements in the United States [12]
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