Clinical Efficacy of Propolis for Treating Dysmenorrhea
Primary dysmenorrhea (PD) is a condition that causes abdominal cramping during menstruation. PD affects 60-93% of women in their reproductive years and typically occurs in adolescents and young women without associated pelvic pathology. Risk factors include age <20 years, family history of PD, tobacco (Nicotiana tabacum, Solanaceae) smoking, heavy or irregular menstruation, menarche at <12 years of age, low weight, and nulliparity. PD pain is caused by excess prostaglandin production in the uterus during ovulation, leading to uterine contractions and ischemia. Non-steroidal anti-inflammatory drugs (NSAIDs) and oral hormone contraceptives used for PD may have severe adverse effects (AEs).
Many complementary and alternative medicine (CAM) therapies have been investigated for treating PD, including herbs, dietary supplements, behavioral interventions, spinal manipulation, acupressure, acupuncture, and transcutaneous electrical nerve stimulation (TENS). Honeybee products, including honey, bee pollen, royal jelly, and propolis*, are used in many traditional CAMs. Traditional Iranian (Persian) medicine uses propolis for PD. One study reported propolis improved chronic backache, hip pain, and pain of acute injuries to muscles and tendons. In another, honey and mefenamic acid, an NSAID, relieved PD pain similarly. In yet another report, honey and bee larvae were used to treat the pain of menstruation and post-parturition disorders.
The authors conducted a double-blind, randomized, placebo-controlled clinical trial (RCT) of the effect of propolis on PD pain. Participants were female students at Hamadan University of Medical Sciences (Hamadan, Iran) in 2018. They were single; 19-23 years old; had histories of regular, consecutive menstrual cycles; did not use any medication for PD; did not use hormonal drugs; had no history of major psychological disorders, and had scored ≥3 on a 10 mm visual analog scale (VAS) assessing PD pain. Exclusion criteria included intolerance to the study drug, improper use, or discontinuing the study regime. Ultrasound was used to rule out secondary dysmenorrhea due to uterine pathology, e.g., endometriosis.
After screening 126 female students for eligibility, 86 were randomized into two groups. At baseline, their age, age at menarche, and body mass index (BMI) were recorded as well as a baseline (cycle 0) pain VAS.† The placebo group received 500-mg “starch” capsules to be taken once daily beginning two days before the start of their next two menstrual periods (cycles 1 and 2) until the third day of menstruation in each cycle. The active group, using the same schedule, received 500 mg propolis capsules (Shahd Golha Honey Co.; Isfahan, Iran). Blinding measures are not reported.
VAS scores at cycles 1 and 2 were compared with those at cycle 0. Quantitative variables are reported as means ± standard deviation. Continuous variables were compared using Student’s t-test. P<0.05 was considered significant.
At baseline, there were no significant between-group differences in students’ mean age, age of menarche, BMI, or VAS scores (P=0.096 for the latter). Of 43 randomized to each group, 40 in placebo and 43 in the propolis group completed the study. From cycle 0 to cycle 1, and again from cycles 1 to cycle 2, VAS scores fell significantly in the propolis but not the placebo group. Mean cycle 0 VAS=6.86±1.79 fell to 5.32±2.28 in cycle 1 in the propolis group while the placebo group’s mean cycle 0 VAS=7.45±1.33 remained at 7.40±1.21 in cycle 1 (P<0.001). The active group had mean VAS=4.74±2.40 in cycle 2 vs. the placebo group’s 7.17±1.24 (P<0.001). No AEs were reported.
While this study supports the use of bee propolis as an alternative to NSAIDs for relief of PD pain, its limitations include a small sample size and short duration. The population included only single women with an average age of 21 years, limiting generalizability. Also, the study agent was not chemically characterized. Given the many propolis compounds and the preclinical and clinical results reported for some, the authors’ brief mention of propolis’ high isoflavone content, potentially exerting numerous effects, is insufficient. They cite reports of smooth muscle relaxation caused by three derivatives of p-coumaric acid from “a Brazilian [propolis] sample” without apparent regard for the extreme variability of propolis content. Nonetheless, the lack of AEs in this study, and propolis’ long history of safe use offer good news to women who experience PD.
*According to HerbClip 081843 [not published yet], propolis, a resinous substance, is made by honey bees using saliva, beeswax, and plant exudates to seal, protect, and disinfect hives. Different propolis types are identified by color, e.g., red, green, and brown, but within these, the composition varies by bee species, region, hive, the botanical source of exudates, collection season, and extraction solvents. Propolis has unique bioactive compounds and, despite variances, has been used medicinally by humans since about 300 BCE.
†Whether this was the same as the eligibility VAS assessment is unclear, as is the timing of the screening process vis-a-vis potential participants’ menstrual cycles.
Jenabi E, Fereidooni B, Karami M, Masoumi SZ, Safari M, Khazaei S. The effect of bee propolis on primary dysmenorrhea: a randomized clinical trial. Obstet Gynecol Sci. September 2019;62(5):352-356. DOI: 10.5468/ogs.2019.62.5.352.