From the Research
Evening primrose oil is not recommended for cervical ripening due to limited and inconsistent evidence supporting its effectiveness, and its use remains controversial in conventional obstetric practice. The oil contains gamma-linolenic acid (GLA), which may theoretically help soften the cervix by promoting prostaglandin production, but clinical studies have not consistently demonstrated significant benefits 1, 2. Typical dosing in studies ranges from 500-2000mg daily, usually taken orally in capsule form during the final weeks of pregnancy (from about 37 weeks). However, some studies have suggested that evening primrose oil may be effective in cervical ripening when used vaginally, rather than orally 3, 4.
Some key points to consider:
- The use of evening primrose oil for cervical ripening is not supported by strong evidence, and its effectiveness is still a topic of debate 1, 2.
- Alternative methods for cervical ripening, such as membrane sweeping, prostaglandin preparations, and mechanical methods like Foley catheter insertion, have stronger evidence supporting their use 1.
- Women considering evening primrose oil should discuss it with their healthcare provider before use, as safety data is limited, and it may interact with certain medications, including anticoagulants and antiplatelet drugs 5.
- The body naturally produces prostaglandins as pregnancy approaches term, which gradually soften the cervix in preparation for labor, making the need for evening primrose oil questionable 1.
In terms of specific studies, a 2021 systematic review and meta-analysis found no significant difference between the intervention and control groups in terms of mean difference of the Bishop score before and after intervention 1. However, a 2023 study found that 2000 mg of vaginal evening primrose oil was significantly more effective for cervical ripening than 200 μg of vaginal misoprostol before gynecological surgery 3. A 2022 randomized controlled trial also found that evening primrose vaginal capsules can reduce the length of the first stage of labor, improve Bishop score, and soften and ripen the cervix 4.
Overall, while some studies suggest that evening primrose oil may be effective in cervical ripening, the evidence is limited and inconsistent, and its use remains controversial in conventional obstetric practice. Therefore, it is not recommended to use evening primrose oil for cervical ripening without consulting a healthcare provider and considering alternative methods with stronger evidence.