Systematic Review of Evening Primrose (Oenothera biennis) Preparations for the Facilitation of Parturition

Abstract

Background: The objective of this systematic review was to characterize the efficacy and safety of evening primrose (EP) for facilitation of parturition in peripartum persons. Methods: This search sought records related to the efficacy and safety of EP preparations to facilitate parturition. Eligibility criteria were primary literature with efficacy or safety outcomes reported; studied in peripartum persons; and available in English. Records were excluded if they were available as abstracts only. Data was synthesized by study characteristics, patient demographics, and outcomes. The RoB2 and ROBINS-I were used to assess risk of bias. Results: A total of 11 studies met inclusion criteria: seven randomized placebo-controlled trials, one randomized non placebo-controlled trial, one case study, one observational retrospective study, and one quasi-experimental cross-sectional study. Efficacy outcomes included Bishop scores and duration of labor during the different phases. Reported adverse events were generally mild and included increased blood pressure, decreased heart rate, pain, bleeding, nausea, and vomiting. Important risks of bias exist across the literature reviewed. Conclusion: The use of EP for parturition in peripartum individuals is not recommended. Further research is warranted before use during parturition or the peripartum period. Other: The authors deny conflicts of interest. The study was neither registered nor funded.

Evening primrose oil: a comprehensive review of its bioactives, extraction, analysis, oil quality, therapeutic merits, and safety

“…For short-term use, the normal oral dose is 6 g per day; however, there is no recommended topical or vaginal dose in previous guidelines. 33 From 2.7 to 4.4 h, GLA was found to reach the highest plasma level. However, the topically or vaginally administered EPO has not been investigated yet regarding its absorption rate, distribution in tissues, metabolism, and excretion.…”

“…However, the topically or vaginally administered EPO has not been investigated yet regarding its absorption rate, distribution in tissues, metabolism, and excretion. 33 Another clinical study in 6 healthy volunteers receiving six capsules of Epogam® (total dose being 240 mg of GLA) twice daily showed that absorption from the digestive tract is significantly lower in the morning compared to the evening. 34 Liquid EPO has been reported to deliver pure oil in a readily absorbable form.…”

“…It is also advised that individuals who have a surgery scheduled within the next two weeks abstain from consuming products containing EPO. 33 In addition, environmental contaminants were detected in commercial EPO, where polycyclic aromatic hydrocarbons (PAHs) were identified in oil products marketed in São Paulo (Brazil). Examples include benzo[a]anthracene, chrysene, benzo[b]fluoranthene, and benzo[a]pyrene, reaching 14.99 μg kg −1 .…”

“…EPO is marketed in the form of liquid oil, capsules, and pill dosages containing 0.1–1.35 g in addition to topical and vaginal formulations. 33,34 Examples include Efamol®, Efalex®, Epogam®, and Efanatal®. Clinically assessed EPO products typically encompass 8–10% GLA, 70–75% LA, 5–6.5% palmitic acid, 6.4–11.8% oleic acid, and 1.8–2% stearic acid.…”

“…It is also advised that individuals who have a surgery scheduled within the next two weeks abstain from consuming products containing EPO. 33…”