Evening primrose oil is commonly used as an alternative therapy, popular among women's health providers and midwives, and it is rich in omega-6 fatty acids. It's best known for its use in the treatment of systemic diseases caused by inflammation, such as atopic dermatitis and rheumatoid arthritis. It is often used for several women's health conditions, including breast pain (mastalgia), menopausal and peri-menopausal symptoms, cervical ripening in preparation for labor, and even labor induction or augmentation (Bayles & Usatine, 2009). However, as much of a lover of botanical medicine that I am, this is one I tended to shy away from as a midwife for labor induction purposes. I'll share why, as well as the results of newer studies evaluating evening primrose oil as a natural option for labor induction.
Evening primrose oil (EPO) is obtained by cold expression or solvent extraction from the seeds of the evening primrose plant (Oenothera biennis) (Bayles & Usatine, 2009). It is native to North and South America and is now widespread through Europe and parts of Asia. This biennial plant is also known by the names tree primrose, sun cups, sundrops, king's cure-all, fever plant, evening star, and night willow-herb.
The stems are mucilaginous and the juices of the leaves healing as well, so Native Americans used this plant as a remedy for soothing cutaneous inflammations, or they would create poultices of the plant and treat bruises and minor wounds (Libster, 2002). Internally the leaves were used for gastrointestinal ailments and sore throats.
Evening Primrose oil is being studied for its use in diabetes, cancer, asthma, preeclampsia, schizophrenia, and attention deficit hyperactivity disorder. Most studies to date have significant limitations, but EPO theoretically holds promise for a wide range of conditions, given its involvement in the metabolism of prostaglandins and leukotrienes; however, the fact remains, we really haven't the clarification needed to understand clinical claims made for EPO or optimal dosing.
How Does Evening Primrose Work?
The seeds of the evening primrose are rich in omega-6 essential fatty acids, including linoleic acid and gamma-linolenic acid. The therapeutic action then is contributed to the direction action of these oils on our immune cells, as well as their indirection action on the synthesis of prostaglandins, cytokines, and cytokine mediators (Bayles & Usatine, 2009), which has caused researchers to theorize that evening primrose oil may be effective as a natural labor inducer in childbearing women. There are super small studies demonstrating it is effective for softening the cervix in both postmenopausal and women who have never birthed children, prior to procedures that require passage through the cervix (Aquino et al., 2011).
Dietary omega-3 and omega-6 essential fatty acids can reduce the effects of highly unsaturated fatty acids in tissues and eicosanoid actions, which have been implicated in various inflammatory and immunologic pathogeneses. In layman's terms, evening primrose oil is the good fat that soothes the damage and inflammation caused in our bodies from the bad fats we consume.
Breast Pain, Menopause & Peri-Menopausal Symptoms
The literature isn't overwhelming when it comes to demonstrating that evening primrose oil is effective at reducing breast pain; this doesn't mean it isn't, but simply that the research hasn't yet helped us understand this role (Bayles & Usatine, 2009). The same is true for menopause and peri-menopause; there isn't a lot of support, or understanding, yet in the literature. It is widely used for this purpose, which demonstrates a historical belief that this was beneficial, as well as a very limited history of negative consequence, but this has yet to present itself yet in the science.
Diabetic Neuropathy
There are several small studies that suggest that oils derived from evening primrose oil may be useful in diabetic patients with mild to moderate diabetic neuropathy who achieve only partial relief from prescription drugs (Halat & Dennehy, 2003; Keen et al., 1993; & Jamal & Carmichael, 1990).
Rheumatoid Arthritis
A Cochrane review evaluating oils from primrose oil, borage oil, and black currant seed oil with placebo has found there isn't a lot of support here for this recommendation, specific to rheumatoid arthritis (Little & Parsons, 2001).
Midwifery Uses in Pregnancy & Birth
When I was catching babies, EPO was a common recommendation for ripening the cervix. Midwives would apply this, or encourage clients to apply EPO intra-vaginally, and the belief was that it would accelerate cervical ripening, shorten labor, and decrease the incidence of post-date deliveries which is a significant concern in many practices because they work within collaborative agreements that restrict their ability to make clinical decisions independently, or even state law may prohibit their scope.
However, I didn't have such restrictions, so knowing there were no random control trials to support this intervention (Bayles & Usatine, 2009), which in itself isn't a huge deal, I discouraged EPO because it had been associated with more protracted phase of labor and increased incidence of premature rupture of membranes, arrest of descent, oxytocin administration, and vacuum extraction (Dove & Johnson, 1999). While post-dates may give anxiety to many midwives, premature rupture of membranes was the bane of my existence as a midwife so I avoided this like the plague.
Are there Any Concerns with Evening Primrose Oil?
EPO is generally well tolerated. Any concerns have largely resolved around gastrointestinal issues, such as abdominal pain, indigestion, nausea, and soft stools. Some have complained of headaches. Certainly, when generations have encouraged botanical therapies for particular remedies, especially through various cultures, there is a lot of respect to be given there and where there are few side effects, I am happy to lean into its use. All by itself, primrose oil does offer us the benefit of essential fatty acids which are great for us during all seasons of our lives, but with my midwife cape on, I have a little different perspective.
I recognize this is a bit of a stretch and an opinion of myself alone, but as a midwife who attended women in the home setting, including about 100 women who had previously had a cesarean section, I did not feel comfortable introducing EPO in these scenarios. One of the pharmacologic effects, or indirect actions, of EPO was its influence on prostaglandins. My concern was that prostaglandins have been known to increase the incidence of uterine rupture so until this was better understood with EPO, it was not worth the risk in my opinion, add to that the potential for it causing a more challenging labor and birth with premature rupture of membranes, protracted labor, or more challenging second stages. No thank you.
Midwives, what's your opinion?
References
Aquino, P. A., Fernandes, H. D., Garcia, M. I., Barrientos, M. A., Apepe, E. T. B., & Pichay, R. L. (2011). Determining the ease of cervical dilation in patients given evening primrose oil (Eveprim) intravaginally before hysteroscopy in postmenopausal and nulliparous, premenopausal women ages 37-77 years old: a pilot study. JMIG, 18(6), 126-127.
Bayles, B. & Usatine, R. (2009). Evening primrose oil. American Family Physician, 80(12), 1405-1408.
Dove, D. & Johnson, P. (1999). Oral evening primrose oil: its effect on length of pregnancy and selected intrapartum outcomes in low-risk nulliparous women. Journal of Nurse-Midwifery, 44(3), 320-324.
Halat, K. M. & Dennehy, C. E. (2003). Botanicals and dietary supplements in diabetic peripheral neuropathy. Journal of American Board of Family Practice, 16(1), 47-57.
Jamal, G. A., & Carmichael, H. (1990). The effect of gamma-linolenic acid on human diabetic peripheral neuropathy: a double-blind placebo-controlled trial. Diabetic Medicine, 7(4), 319-323.
Keen, H. Payan, J. & Allawi, J. (1993). Treatment of diabetic neuropathy with gamma-linolenic acid. The gamma-Linolenic Acid Multicenter Trial Group. Diabetes Care, 16(1), 8-15.
Libster, M. (2002). Delmar's Integrative Herb Guide for Nurses. Delmar/Thomson Learning.
Little, C. & Parsons, T. (2001). Herbal therapy for treating rheumatoid arthritis. Cochrane Database Systematic Review, (1), CD002948.
コメント