Painful Periods: Dysmenorrhea and Essential oils – Part II

by Camille Charlier

Modern Treatment Strategies

Nonsteroidal anti-inflammatory drugs are the first line of treatment by clinical specialists for Primary dysmenorrhea (PD). The most commonly used NSAIDS for menstrual pain are aspirin, ibuprofen, mefenamic acid and naproxen. They work to reduce pain in dysmenorrhea by inhibiting the action of cycooxygenase (COX), an enzyme responsible for prostaglandin production. There may also be direct analgesic action on the central nervous system. A 2015 meta-analysis of 80 randomized controlled clinical trials found that NSAIDS were more effective for pain relief than placebo (18% of those taking placebo achieved moderate to excellent pain relief, compared with the same level of pain relief in 45-53% of those taking NSAIDs). That being said, most of the studies were commercially funded (59%), and a further 31% failed to disclose their funding source, indicating possible conflicts of interest and bias. Subjects using NSAIDS also experienced more adverse effects than the placebo groups, including negative gastrointestinal (nausea and indigestion) and neurological effects (headache, drowsiness, dizziness and dryness). The evidence indicates that if 10% of those taking placebo experience side effects, 11-14% of those taking NSAIDs will do so [11].

Morrow and Naumburg point out that “an estimated 10% to 25% of women either do not respond to NSAIDs or choose not to use them because of side effect profiles, intolerance, or discomfort with medication usage.” They add that “Millions of women seek alternative, complementary, or natural remedies for the discomfort of menstrual pain and there are numerous effective treatments that can offer relief.” One of the primary problems with complimentary treatments such as acupuncture, exercise, nutritional supplementation, and aromatherapy is a lack of research to assess their efficacy and safety. The reason for lack of research? No funding.

Morrow and Naumburg conclude: “[Complementary] therapeutic options are difficult to study in controlled trials and may not have inherent financial incentives that promote study interest and sponsorship, yet the absence of rigorous supporting literature should not dissuade the clinician from considering them as viable options. [14].

Complementary and Alternative Interventions: Aromatherapy

Considering the limited efficacy of the standard treatment and its host of unpleasant side effects, it is unsurprising that those suffering from dysmenorrhea seek alternative strategies of pain reduction. One complementary therapy for dysmenorrhea that has received attention in the research community is aromatherapy. A rich tradition of aromatherapy usage for dysmenorrhea combined with promising animal experiments has led to a number of clinical trials.

A search of the PubMed database using the terms ‘essential oil’ and ‘dysmenorrhea’ with a “human” filter produced 14 results, while the terms ‘aromatherapy’ and ‘dysmenorrhea’ with the “human” filter drew 10, with the majority of research on essential oils emerging in the last two decades. Aromatherapy is a multidimensional treatment strategy with negligible side effects. It can be used via inhalation, massage, or as an adjunct to standard medical approaches; one study found essential oils acted as penetration enhancers for transdermal administration of Ibuprofen in dysmenorrhea model mice [4]. As women assert increasing dominance in the workforce, we can expect the demand for safe and effective therapies to prevent their absence from work and school to likewise increase.

The published research on the use of aromatherapy for treating symptoms of dysmenorrhea is consistently positive. A 2017 meta-analysis presented in Complementary Therapies in Clinical Practice analyzed six randomized controlled clinical trials, a total of 362 participants, to compare the efficacy of abdominal aromatherapy massage vs. placebo massage in reducing symptoms of primary dysmenorrhea. Pain was assessed via the visual analog scale and compared across menstrual cycles before and after treatment.

The researchers concluded that abdominal massage with essential oils was markedly more effective in reducing pain than massage alone [22].

Meta-analyses are useful for increasing sample sizes and statistical power, but even when adhering to rigorous standards their quantitative results should be interpreted with caution due to the heterogeneity of the included studies, as well as selection and publication biases. Let’s bolster these findings, then, with some individual studies. A 2015 article published in the Journal of Obstetrics and Gynaecology investigated the efficacy of abdominal self-massage with Rosa damascena essential oil on PD. 75 students were divided into three groups – one with rose oil diluted in almond oil, another with almond oil alone, and a third with no treatment – and instructed to perform self-massage. Severity of pain was measured via the visual analog scale (VAS), which was taken before and after intervention. Self massage was performed on the first day of menstruation for two subsequent cycles. The three groups were matched for demographic characteristics. Results showed that, while baseline pain was reduced in all three groups in the first cycle, it was not statistically significant. In the second cycle, however, the rose oil group showed a significant drop in pain scores compared with the other two groups following intervention [19].

A 2013 study published in Evidence-Based Complementary and Alternative Medicine used a randomized blind clinical crossover study to examine the effect of abdominal massage with cinnamon, clove, rose, and lavender essential oils on nursing students suffering from primary dysmenorrhea. The treatment group received abdominal massage with essential oils diluted in almond oil once daily for one week prior to menstruation, while the placebo group received the same intervention but with almond oil alone. Each group was evaluated at baseline and again after treatment. After completing the first trial, the groups switched treatment regimen and the protocol was repeated. In both treatment phases the severity and duration of menstrual pain as well as volume of menstrual bleeding was significantly reduced in the aromatherapy group as compared to placebo. The authors note that strategies for addressing menstrual pain are highly culturally contingent – 75% of secondary school students from urban and rural areas in Mansoura, Egypt suffered from dysmenorrhea (55.3% rated mild, 30% moderate, and 14.7% severe), but it is not considered a problem which warrants medical intervention. Importantly, adolescents with dysmenorrhea preferred not to take medication for their symptoms out of concerns of substance dependence and infertility. In light of this, complementary therapies for pain reduction are of particular significance [12].

Another study published in the Journal of Obstetrics and Gynaecology Research in 2012 found that abdominal self-massage with essential oils provided relief for outpatients with PD and reduced the duration of menstrual pain. 48 outpatients diagnosed with PD by a gynecologist were divided into two groups; the experimental group received essential oils of lavender, clary sage, and marjoram in a 2:1:1 ratio diluted to 3% in an unscented jojoba cream at a dosage of 2 g/day, while the control group was given a synthetic fragrance diluted in jojoba cream. Demographically, the participants ranged in age from 19-45 years, 77% had experienced dysmenorrhea for over three years, and 50% of the participants had never used analgesics. One criterion of inclusion was that participants had at least one menstrual cycle in the previous year, which the authors charmingly referred to as a “menstrual experience.”

Pain levels were evaluated with a 10-point numeric rating scale (NRS) and verbal rating scale (VRS) pre-intervention, on the first three days of the first menstrual cycle concurrent with the intervention, and post-intervention on the first three days of the subsequent cycle. The researchers observed a statistically significant reduction in the duration of pain in the aromatherapy group but not in the synthetic fragrance group, as well as a greater drop in the severity of pain from the first to the third days of menstruation. None of the participants in the aromatherapy group required analgesics after the intervention.

The researchers also performed gas chromatography on the essential oil blend to identify its constituents and found the top five contents to be: linalyl acetate (36.84%), linalool (22.53%), eucalyptol (17.21%), aterpineol (3.29%), and b-caryophyllene (2.69%). The analgesic effects of the essential oil blend are attributed to these compounds, but the authors attempt to tease out potential confounding factors of the effects of massage, writing:

Massage can reduce stress hormone levels by excreting endorphins in the plasma, promoting parasympathetic activation, and increase secretion of the neurotransmitter serotonin to block the conduction of pain. Indeed, massage may possess positive influences on relieving menstrual pain. However, it has no persistent analgesic efficacy, only temporary efficacy… after massage therapy. The efficacy of pain relief was due to certain components in the massage cream, and not to the practice of massage itself in our study.

The authors note that aromatherapy has a “positive influence on the autonomic nervous system, releasing anxiety, and controlling pain,” an outcome they attribute not just to the scent of the essential oils, but to transdermal absorption of their chemical constituents. The mechanism of action likely involves inhibition of prostaglandin secretion by linalool, which results in decreased myometrial contractility. Eucalyptol (1,8-cineole), a terpene oxide found in marjoram oil, inhibits the metabolism of arachidonic acid, a precursor to PGs found to have inflammatory effects on human blood monocytes. B-caryophyllene, a terpene, also exerts local anesthetic activity [16].

A randomized placebo-controlled trial published in 2006 in the Journal of Alternative Complementary Medicine found that abdominal self-massage with almond oil and aromatherapy was more effective at relieving dysmenorrhea than almond oil self-massage alone. In this study 67 college students with a menstrual pain ranking of 6/10 or higher on the visual analog scale were divided into experimental, placebo, and control groups. The experimental group performed self massage with 5 cc of almond oil to which essential oils had been added – 2 drops lavender (Lavandula officinalis), 1 drop rose (Rosa centifolia), and 1 drop clary sage (Salvia sclarea). The placebo group performed self massage with 5 cc of almond oil, while the control group received no treatment. Intensity of pain was measured via the visual analog scale, while severity of dysmenorrhea symptoms were assessed with a multidimensional scoring system designed to assess the impact of dysmenorrhea on daily life.

Aromatherapy self-massage was found to reduce the intensity of menstrual pain compared to placebo and control, as well as to significantly reduce the severity of dysmenorrhea impact on the first and second days of menstruation. Aromatherapy treatment resulted in a pain score drop from 7.40 to 4.26 on the first day of menstruation [7].

One limitation of these studies is the inconsistency inherent in self-massage as part of a treatment protocol. A 2012 study published in the journal of Pain Management Nursing controlled for this variable by having one practitioner perform abdominal massage on all the participants at a regularly scheduled time of day. In this trial, standardized abdominal massage with lavender oil was found to be more effective at reducing menstrual pain than massage with odorless liquid petrolatum. The experimental design consisted of a randomized crossover design, wherein 44 volunteers with PD received 15 minutes of abdominal massage with lavender oil or placebo oil. The results were measured via visual analog scale at baseline and post-treatment. Participants were monitored for three menstrual cycles: One observational period without treatment, followed by treatment/placebo for the next cycle, with the treatments swapped in the third cycle. A reduction in pain was observed in both placebo and experimental groups, but the degree of pain reduction was significantly greater in the lavender oil group than the petrolatum group – pain levels as measured by a 100-point VAS scale dropped from 82.38 to 51.13 after aromatherapy massage, compared with 82.38 to 74.31 after placebo massage [2].

Aromatherapy has also been shown to be effective in treating dysmenorrhea in the absence of abdominal massage, through inhalation alone. The Annals of Medical and Health Sciences Research published a study in 2016 on the effect of lavender aromatherapy on pain severity in primary dysmenorrhea. In this triple-blind randomized clinical trial, 200 individuals between the ages of 19 and 29 with PD were divided into two groups: one was exposed to lavender essential oil, and the other to diluted milk as a control. Each group received 10 cc of their respective substance and were instructed to drip three drops onto a piece of cotton, and to smell it once daily for 30 minutes on the first three days of their cycle for two consecutive cycles. Pain was quantified via the visual analog scale (VAS) which was submitted via questionnaire on the cycle previous to treatment (Cycle-0), and the two subsequent cycles. The researchers found that the group exposed to lavender essential oil experienced a statistically significant reduction in pain over the course of two cycles as compared to the control group, which had no such reduction. Pain levels were comparable between the two groups prior to treatment [15].

Another randomized clinical study published in Complementary Therapies in Medicine in 2014 found that inhalation of lavender essential oil significantly reduced symptoms of primary dysmenorrhea. In this study 96 Iranian students suffering from PD were divided into two groups. The experimental group was given lavender essential oil diluted in sesame oil at a ratio of 2:1, while the placebo group used sesame oil alone. The subjects were instructed to place three drops of the oil on their palms, rub them together, place their hands at a distance of 7-10 cm from their noses, and inhale for five minutes. This treatment was administered one hour following the onset of dysmenorrhea symptoms, and repeated every six hours for the first three days of menstruation for two consecutive menstrual cycles. Results were measured via a researcher-developed questionnaire based on existing dysmenorrhea literature and designed to assess symptoms from light to severe/debilitating. The volume of menstrual bleeding was measured by a pictorial blood assessment chart before and after treatment. Researchers found that inhalation of lavender significantly reduced symptoms of dysmenorrhea compared to placebo. Menstrual volume was reduced, though the data was not statistically significant, and there was no effect of lavender inhalation on the presence of blood clots [17].

The Iranian Journal of Pharmaceutical Research published a 2003 clinical trial reporting that fennel essential oil (FEO) decreased menstrual pain in those with primary dysmenorrhea. In this randomized double-blind study 60 individuals were treated with placebo, 1%, or 2% FEO in a three-period crossover design.

Presumably this essential oil was taken internally, but the authors don’t explicitly state their method of treatment application, using only the word “administered” to describe theirs. We only know that a dose of 0.3-1 ml was taken starting with the onset of pain “as needed.”

Pain, fatigue, nausea, vomiting, diarrhea, headache, mood, and faintness were measured with a symptom chart. In the placebo group, 66.7% of patients required other medication to relieve symptoms compared to 41.8% of patients in the 1% FEO-treated group and 39.9% in the 2% FEO treated group. Pain scores were significantly reduced following FEO treatment compared to placebo, but there was no effect on other symptoms [10].

One of the benefits of aromatherapy treatment for menstrual pain is that it can be used in conjunction with conventional treatments to enhance their efficacy.

A 2016 study published in Complementary Therapies in Clinical Practice found that aromatherapy with 2% rose essential oil provided pain relief above and beyond NSAID treatment in people diagnosed with primary dysmenorrhea. In this experiment 100 subjects ages 19-30 were randomly divided into two groups, both of which were treated with the NSAID diclofenac sodium (Diclomec 75 mg) via intramuscular injection. Additionally, the experimental group received aromatherapy (2% rose essential oil), while the control group received a placebo (saline spray). Subjective measures were taken at baseline, 10 min post-treatment, and 30 min posttreatment via the visual analog scale (VAS), along with objective measures of respiratory rate (RR), systolic arterial blood pressure (SBP), diastolic arterial blood pressure (DBP), mean arterial blood pressures (MAP), and heart rate (HR). Individuals with systemic disease such as diabetes mellitus, hypertension, and cardiovascular or endocrine disorders were excluded from the study.

Overall, researchers observed that VAS decreased for both groups, but pain improved significantly more in the aromatherapy group than the control group by 30 min post-treatment. The mechanism of action for this pain reduction above and beyond NSAID treatment remains a hotly contested topic, but the authors of this study posit, based on recent studies, that aromatherapy may influence the olfactory-hippocampal pathway which regulates acetylcholine release, thus altering pain sensation. Furthermore, GABAergic and putative neurons (including cholinergic neurons) may be stimulated. The authors elaborate:

Inhalation of essential oils (nice smells) stimulates the olfactory receptors that convey messages to the brain and induces a composition of memory, thought, and emotion. The mixture of stimulations triggers a release of internal chemicals, including enkephalin and endorphin, which reduce pain and anxiety, respectively, and also decrease the levels of epinephrine and norepinephrine by lowering the sympathetic discharge.

Some factors to consider regarding methodology: There were initial differences in diastolic blood pressure, heart rate, and respiratory rate between the two groups prior to treatment, which indicates the possibility of skewed data – DBP and RR were higher in the conventional treatment group, while HR was higher in the aromatherapy group at baseline. Significantly, the subjects of this experiment were selected from a population of individuals admitted to an emergency unit. It is possible that selection bias is at play – perhaps the subjects included in this study suffer worse symptoms of dysmenorrhea than the average population, have lower pain thresholds, or are more likely to seek medical attention than their peers [23].

For a complete listing of references, please see Part I: Painful Menstruation: Dysmenorrhea and Essential Oils here!