The Effect of Evening Primrose Oil on Clinical Symptoms in Women with Polycystic Ovary Syndrome (PCOS): A Randomized Controlled Trial

Abstract

Introduction: Polycystic Ovary Syndrome (PCOS) is one of the most important reproductive and endocrine disorders in women. Evening primrose oil is a phytoestrogenic plant, and there are numerous reports on the effects of phytoestrogens on the hypothalamic-pituitary axis. Given the side effects of existing chemical drugs, the aim of this study was to investigate the effect of evening primrose oil on the clinical symptoms of women with PCOS. Materials and Methods: This triple-blind randomized controlled clinical trial was conducted on 62 women aged 18 to 45 with PCOS who visited the gynecology clinics at Al-Zahra and Taleghani Hospitals, the endocrinology clinic at Imam Reza Hospital, Sina Hospital, and private centers in Tabriz in 2023. Participants were randomly assigned to an intervention group (n=31) and a control group (n=31) using a block randomization method. The intervention group received 1000 mg of evening primrose oil capsules daily for three months, while the control group received a placebo with the same dosage and administration method. Before and after the intervention, the participants completed the Freemann-Halley questionnaire, menstrual bleeding characteristics, Beck Depression Inventory, and the Higham scale. Additionally, anthropometric indices (waist circumference, hip circumference, body mass index) were measured by the researcher. Independent t-tests and ANCOVA, controlling for baseline scores, stratification factors, and potential confounding variables, were used to compare the outcomes between the two groups. Results: After the intervention, based on the ANCOVA test and controlling for potential confounding variables, there were no significant differences between the two groups in terms of mean depression scores (P=0.256), hirsutism (P=0.731), amount of bleeding (P=0.244), waist circumference (P=0.892), hip size (P=0.150), body mass index (P=0.177), interval between menstrual cycles (P=0.968), or duration of bleeding (P=0.789). Conclusion: The findings of this clinical trial showed that the use of evening primrose oil in women with PCOS had no effect on clinical symptoms compared to the placebo. However, further studies are recommended for definitive conclusions in this area.