Dysmenorrhea and premenstrual syndrome (PMS) are prevalent and recurrent conditions that may compromise the well-being and quality of life of women of reproductive age [1]. There are two types of dysmenorrhea: primary and secondary. Primary dysmenorrhea is characterized by spasmodic cramping pain in the lower abdomen accompanied by nausea, vomiting, and diarrhea, and typically lasts between 12 and 72 hours [2]. Primary dysmenorrhea is very common, and more than 50% of teenagers and 30%–50% of menstruating women suffer from various degrees of this discomfort [3]. Secondary dysmenorrhea results from underlying gynecologic disorders such as adenomyosis, uterine fibroid, or endometriosis, as well as other disorders [4]. PMS is characterized by a range of somatic and psychological symptoms that occur during the luteal phase, from ovulation to the onset of menstrual bleeding [5].

The principal underlying cause of menstrual cramps is ischemia, which is due to uterine contractions caused by prostaglandin secretion during menstruation [6]. According to an Indian systematic review, the pooled prevalence of PMS was 43%, and the prevalence of PMS in adolescence was estimated higher than others, and accounted to be 49.6% [7].

Although there is currently no definitive treatment for PMS and dysmenorrhea, different approaches have been adopted to manage symptoms. These include administration of analgesics, anti-inflammatory medicines, and herbal medicine therapy [8]. The first line of treatment for primary dysmenorrhea typically involves non-steroidal anti-inflammatory drugs (NSAIDs) [9]. Additionally, antidepressants and oral contraceptives are also used to manage PMS and dysmenorrhea [8,10]. However, NSAIDs are associated with contraindications, side effects, and a failure rate of approximately 20%–25% [11]. As a result, some women opt for complementary and alternative treatments to alleviate menstrual pain. However, the effectiveness and safety of this type of treatment have not been comprehensively investigated [12]. According to a systematic review in Iran, aromatherapy using Iranian herbs such as lavender and rose may significantly reduce symptoms of primary dysmenorrhea and PMS [13].

A few studies have found that curcumin can alleviate symptoms of dysmenorrhea and PMS [14-16]. curcumin is a yellow polyphenol compound that is the main ingredient of turmeric (Curcuma longa L from the Zingiberaceae family) [17]. It is used as a spice in cooking and as an herb in traditional medicine. Evidence shows that curcumin has pleiotropic effects and acts as an anti-inflammatory, anticancer, antioxidant, and antibacterial agent [18,19]. In addition, curcumin can reduce prostaglandin production [20].

Khayat et al. [15] found that curcumin can alleviate symptoms experienced before menstruation without any adverse effects. Furthermore, curcumin in women with PMS may also regulate neurotransmitters and biomolecules, exert antioxidant and analgesic effects, and reduce oxidative stress [21]. Therefore, the present study aimed to systematically investigate the effects of curcumin on the severity of dysmenorrhea and PMS symptoms.

This systematic review and meta-analysis was conducted in compliance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) checklist [22].

We initially identified 182 published articles after the database search. One hundred forty-seven articles were screened by removing duplicates (n=35); of the remaining articles, seven full-text studies were evaluated in terms of eligibility. Finally, five papers were subjected to quantitative and qualitative analyses [15,24-27]. Figure 1 shows the study flow diagram of the search and selection process of the articles. Two papers were excluded due to wrong outcomes [12,28].

Among the wide variety of natural remedies, turmeric has profound medicinal value, and a large body of research has been conducted on this plant. This meta-analysis included five randomized controlled trials involving 379 women, which indicated that curcumin, a constituent of turmeric, significantly alleviated the severity of dysmenorrhea and PMS compared with placebo. Similarly, curcumin significantly reduced the symptoms of PMS (behavior, mood, and physical disorders).

The present study revealed that curcumin consumption immediately before or during menstruation could alleviate the severity of dysmenorrhea. Delgado et al. [29] in 2018 determined the minimal clinically significant difference in VAS score before and after treatment to be more than 1.4 cm in a 10 cm strip. In our study, the pain reduction rate was 1.25 cm with a 95% CI of 0.98 to 1.52, suggesting that curcumin may be clinically effective in the reduction of dysmenorrhea severity [29]. In line with the present study, limited systematic reviews conducted without undertaking meta-analysis have assessed the effect of curcumin on primary dysmenorrhea and PMS [14,30]. A meta-analysis in 2015 reported that extracts of the Zingiberaceae family (turmeric, ginger, etc.) are effective hypoalgesia agents, even safer than NSAIDs, and can decrease chronic pain [31]. These pain-relieving effects of curcumin are probably due to its anti-inflammatory properties, which down-regulate nuclear factor-kB, and cyclooxygenase 2 (Cox-2) [32]. In-vitro studies have demonstrated that curcumin has anti-inflammatory features by decreasing COX-2 expression and prostaglandin E2 release [33]. In laboratory conditions, curcumin has also been reported to have potential tocolytic effects on non-pregnant mice’s uterine contractions [34], confirming its effectiveness in inhibiting uterine contractions among women with dysmenorrhea.

Furthermore, the present study revealed that curcumin has therapeutic potential for ameliorating premenstrual symptoms. Recently, a systematic review examining the safety and therapeutic effects of Iranian herbal medicine for the treatment of PMS reported that curcumin is an effective and safe remedy for alleviating PMS symptoms [35]. PMS is characterized by physical, emotional, and behavioral symptoms that occur during the luteal phase of the menstrual cycle. It significantly disrupts women’s daily lives, including work and personal activities, and resolves itself automatically within a few days after the start of menstruation. The anti-inflammatory and antioxidant properties of curcumin make it a potential candidate for alleviating physical symptoms of PMS [30], while it influences the behavioral and emotional symptoms through its antidepressant actions (modulating the concentration of neurotransmitters, reducing inflammatory mediators, modulating hypothalamus-pituitary-adrenal disorders, and reducing insulin resistance and oxidative stress substances) [36]. In a study on mice developing behavioral disorders, Abu-Taweel [37] in 2016 showed that curcumin had protective effects on social behavior and could prevent behavioral disorders. In an RCT, curcumin and ginger reduced the severity of psychological, behavioral, and physical symptoms of PMS, with curcumin exhibiting a more profound effect compared to ginger [16]. In two additional studies, the antidepressant effects of curcumin were comparable with the effect of famous antidepressant medications including to those of selective serotonin reuptake inhibitors (fluoxetine and imipramine) [38,39].

A potential limitation of the current study is the poor methodology used in most of the articles we examined. The small sample size, insufficient treatment allocation, imprecise method of blinding, and unspecified randomization technique used in these studies may all have affected the validity of the results. Although we performed a comprehensive search, our assessments may have been influenced by publication bias, which is a common drawback in most medical and health research [40], and this issue may be more pronounced in alternative medicine research [41]. Further research recruiting a larger number of participants from different socioeconomic backgrounds and testing different doses of herbal medicine for longer treatment periods, without the use of a placebo, is recommended to obtain more conclusive results regarding the effectiveness and safety of the tested herbal medicine. Another limitation of this study was that our search was limited to studies published in English.

In conclusion, the findings of our meta-analysis showed that using various forms of curcumin could reduce the severity of PMS and dysmenorrhea owing to its anti-inflammatory and antidepressant activities. Therefore, it could be regarded as an appropriate alternative for women with PMS and dysmenorrhea to improve their quality of life.