Effect of Evening Primrose on Cervical Ripening: A Systematic Review Study

 Background and purpose: Cervical ripening is of great importance in gynecology. Evening primrose is one of the medicinal plants used for cervical ripening and softening before midwifery and labor interventions. The present study aimed to review the clinical trials on the effect of evening primrose on cervical ripening and labor. Materials and methods: In this narrative review, search was done in Scopus, PubMed, Library Cochrane, Embase, Magiran, SID, Web of Science, and Google Scholar to find relevant studies published until May 2020. Clinical studies and quasi-experimental trials published in Persian and English were included. Persian and English keywords including Bishop Score, cervix, evening primrose and their combinations were used. The Jadad scale was used to assess the quality of articles. Results: A total of 283 articles were found and finally 10 interventional studies, including clinical trials and quasi–experimental studies that met the inclusion criteria were reviewed. Among these studies, three were performed on women candidates for gynecological interventions and indicated positive effects of evening primrose on cervical ripening. Other studies were done in pregnant women, but there was not enough evidence on the effect of evening primroses and its effects in pregnancy. Conclusion: No reliable evidence was found on the positive effect of evening primrose on cervical ripening. Therefore, further studies are needed before using this medicinal plant in clinical practice.