Many women suffer from endometriosis, a pelvic disease in which the lining of the uterus occurs outside the uterus. Those affected have to struggle especially with pain in the pelvic area and during menstruation. Other symptoms such as digestive problems, fatigue and depression can have a lasting effect on everyday life. In an evaluation of user data from 2017 to 2020 of the Canadian cannabis app Strainprint, an Australian research team found that medicinal cannabis can alleviate endometriosis symptoms.
Pelvic pain, cramps and gastrointestinal complaints were most often treated with cannabinoids. Nausea, depressive symptoms and reduced libido also benefited. Inhalation followed by oral cannabis products was reported as the most frequent form of application. For pain relief, most women inhaled cannabis products containing mainly tetrahydrocannabinol (THC) – the most important psychotropic cannabinoid. For gastrointestinal complaints and for mood, on the other hand, oral cannabis oils containing the non-psychotropic cannabidiol (CBD) were most commonly used.
Endometriosis – what is it?
In endometriosis, tissue similar to the lining of the uterus also settles outside the uterus, causing chronic inflammation. The disease affects about five to eleven percent of all women of childbearing age. However, two to five per cent also struggle with endometriosis after the menopause. In total, there are an estimated 176 million patients worldwide.
Endometriosis can cause many complaints:
- Chronic pelvic pain
- Gastrointestinal complaints (e.g. painful bowel movements, nausea)
- Pain during menstruation
- Pain during sexual intercourse
- Pain during urination
In addition to persistent pelvic pain, the most common symptom, there may be digestive problems, irritable bowel syndrome and severe fatigue. Endometriosis is often accompanied by anxious and depressive disorders. These symptoms reduce the quality of life of those affected with an impact on many areas of life such as social life, work, education and relationship life.
Retrospective analysis of 19,187 records from a cannabis app
Researchers from the University of Western Sydney and the University of Melbourne, Australia, conducted a retrospective review of available user data from the Canadian mobile phone app Strainprint. 252 participants completed 16,193 treatment sessions over almost three years (April 2017 to February 2020), of which 16,187 records were scientifically analysed. The women were on average 33.1 years old and used the programme for an average duration of 5.5 months. The smartphone programme contains data on about 6,500 laboratory-tested Canadian medical cannabis products with product information such as cannabis variety, content of the cannabinoids THC and CBD as well as the terpene profile.
Before treatment, women indicated the symptoms they wanted to treat and rated the severity on a scale of 0 to 10. In the app, users recorded cannabis type, dosage, cannabinoid ratio between THC and CBD, and method of administration (e.g. oral, inhalation). After use, the users rated their complaints again using the scale. The researchers investigated the effects on common endometriosis complaints: Cramps, pelvic pain, nausea, pain in the gastrointestinal tract, depression and reduced libido.
Inhaled and oral cannabis products most commonly used
Cannabis was used in different ways:
- Inhalation (67.4 %)
- Oral ingestion (32.3 %)
- Topical application (0.2 %)
- Transdermal application (0.1 %)
The most common mode of application was inhalation: about two thirds of the women inhaled cannabis products, of which most (40.6 %) applied cannabis by vaporising with a vaporiser. About a quarter smoked cannabis and a few women inhaled concentrates. Inhaled cannabinoids have the advantage that they take effect within 5 to 10 minutes and therefore offer fast relief from acute symptoms.
Oral ingestion was mentioned second most often: About one third (32.3 %) of the app users took cannabis by mouth, of which the majority (25.0 %) used cannabis oils. Solid dosage forms for swallowing, edible cannabis products – so-called edibles – as well as tinctures were less represented. Oral dosage forms have a slower onset of action of 45 to 180 minutes compared to inhalation. However, the duration of action is longer at 6 to 8 hours and the blood levels are more consistent, which can alleviate long-lasting chronic symptoms in particular.
In the available data, topical, i.e. local applications, were superior to oral intake. However, the information should be interpreted with caution, as only a minimal fraction (0.1%) of patients used topical cannabinoids. Topical cannabis preparations can help especially with localised complaints. However, the study situation is currently very thin.
Endometriosis can bring acute and chronic symptoms, which is why both inhaled and oral applications can be useful.
Pelvic pain and digestive complaints most frequently treated
Ailments treated with cannabis:
- Pelvic pain (42.4 %)
- Gastrointestinal complaints (15.2 %)
- Cramps (14.9%)
- Nausea (13.9%)
- Depression (13.2%)
- Decreased libido (0.3%)
With 42.4 percent, most women used cannabis to relieve pelvic pain, whereby mostly inhaled dosage forms were preferred, possibly due to the faster onset of action. Another advantage of inhalation is the easier control of the effect.
About one in six women used cannabis for gastrointestinal complaints. In contrast to pain relief, oral cannabis preparations were preferred for digestive complaints and depressive symptoms. It is possible that the tendency for the higher CBD content of oral cannabis products contributes to the more effective effect.
The THC and CBD concentrations of the cannabis products used varied depending on the mode of ingestion. For inhalation, mostly THC-dominant cannabis strains were used, while for oral use, more CBD-dominant cannabis products were used.
Endometriosis and the Endocannabinoid System (ECS)
Recent studies showed that endometriosis may be associated with dysfunction in the endocannabinoid system (ECS). A study published in 2019 showed that modulating the ECS may be a way to relieve pain in endometriosis. The cannabinoids THC and CBD can relieve various symptoms of endometriosis and digestive complaints. The psychotropic THC has been shown to relieve nausea and vomiting. Non-psychotropic CBD has anti-inflammatory and antioxidant effects..
Animal models showed that CBD increases the levels of the endocannabinoid anandamide by inhibiting the enzyme fatty acid amide hydrolase (FAAH) and thus has an anti-inflammatory effect. Anti-nausea effects and good effects in gastrointestinal disorders have also been described for CBD. A malfunction of the ECS is also suspected in irritable bowel syndrome with a clinical endocannabinoid deficiency. CBD also influences serotonin receptors (5-HT1A receptors) and thus relieves depression and anxiety. In deep infiltrating endometriosis (TIE), affected women also benefit from the muscle relaxing effect of cannabinoids, which relaxes the tense pelvic floor muscles.
Clinical studies needed
According to the research team, the retrospective cross-sectional study also has limitations. For example, only women who already regularly use cannabinoids as users of Strainprint were reached. In the study period from April 2017 to February 2020, medical cannabis flowers were mostly available in Canada, which may also be a reason for the predominantly inhaled use. On average, women recorded 64.2 treatment sessions, suggesting that data entry continued with good effect.
The evaluation showed that cannabis could have an effect on all reported symptoms. For abdominal pain, inhalation seems to be preferred due to rapid pain relief. Digestive complaints and mood disorders might benefit more from oral cannabinoids with higher CBD content. However, clinical trials with affected women are needed to investigate efficacy, safety and tolerability in endometriosis.
Sinclair J, Collett L, Abbott J, Pate DW, Sarris J, Armour M. Effects of cannabis ingestion on endometriosis-associated pelvic pain and related symptoms. PLoS One. 2021;16(10):e0258940. Published 2021 Oct 26. doi:10.1371/journal.pone.0258940