Perceived impact of medicinal cannabis on pelvic pain and endometriosis related symptoms in Aotearoa New Zealand: an observational cohort study

Abstract

Background

Endometriosis, characterised by the growth of endometrial-like tissue outside the uterus, often causes severe pelvic pain, dysmenorrhea, and fatigue. Current medical treatments frequently provide incomplete symptom control and/or significant side effects. Many individuals with endometriosis report symptom improvements with cannabis use, but high-quality evidence remains limited.

Methods

A prospective, mixed-methods cohort study was conducted. Participants aged 18–50 years with surgically or clinically diagnosed endometriosis self-engaged with a specialist consultant and were prescribed medicinal cannabis (cannabidiol [CBD] oil alone or in combination with dried cannabis flower). Weekly pain scores, and health-related quality of life (measured by the Endometriosis Health Profile-30 [EHP-30]) were assessed via surveys and standardised questionnaires over three months. Completion interviews were conducted to explore participants’ experiences with medicinal cannabis in greater depth.

Results

Participants reported limited adverse events during the study period. Pelvic pain scores decreased over 12 weeks: ‘overall’ pain reduced from 5.46 ± 1.55 (95% CI 0.57) to 3.77 ± 2.25 (95% CI 0.83), and ‘worst’ pain decreased from 7.62 ± 1.51 (95% CI 0.56) to 5.38 ± 2.69 (95% CI 1.00). The mean total EHP-30 score significantly decreased from 68.77 ± 15.17 (95% CI 5.61) to 37.40 ± 16.66 (95% CI 6.17). Qualitative analysis identified four major themes: motivations for seeking medicinal cannabis, experiences of use, barriers to use, and stigma.

Conclusions

Medicinal cannabis use was associated with reduction in pain measures and improvements in quality of life among some individuals with endometriosis during this study. Qualitative findings highlighted both perceived benefits and ongoing challenges related to access, dosage and social stigma. These results support the need for larger controlled studies to further evaluate the safety, efficacy, and long-term outcomes of medicinal cannabis as an adjunctive therapy for endometriosis-related pain.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12906-025-05189-y.

Background

Endometriosis is a systemic inflammatory condition where endometrial-like tissue grows outside of the uterus, generally within the pelvis and on associated pelvic organs [1]. Prevalence is difficult to measure due to the historical difficulties in diagnosis but endometriosis affects around 1 in 9 women and those presumed female at birth in Australia by age 44 [2] and is likely to have a similar prevalence in Aotearoa New Zealand (NZ). Symptoms can include severe and debilitating dysmenorrhea, non-cyclical pelvic pain, dyspareunia, dyschezia and dysuria alongside other comorbidities such as fatigue and reduced fertility [3].

Current treatments available for endometriosis include hormonal medications, laparoscopic surgery, and analgesics (frequently opioids) [4]. However, side effects and discontinuation rates are high [5] and people with endometriosis report low satisfaction with medical management [6]. Hence, novel, non-addictive pain management options are considered a research priority in endometriosis [7].

One pathway which holds potential for targeted treatment is the endocannabinoid system (ECS). The ECS is a relatively recent scientific discovery, largely uncovered through research into the Cannabis genus during the 1980s and 1990s. It is composed of three major components: G-protein-coupled cannabinoid receptors (CB1 and CB2), endogenously produced cannabinoids (endocannabinoids), and the enzymes involved in their synthesis and degradation [8]. The ECS has extensive involvement throughout female reproductive tissues [9], suggesting a potential role in endometriosis pathophysiology [10]. Modulation of the ECS by phytochemicals found in cannabis represents a novel treatment pathway that may effectively reduce endometriosis-associated pain [11, 12]. There is some preliminary evidence of ECS dysregulation in women with endometriosis, including increased levels of anandamide (AEA) and 2-arachidonoylglycerol (2-AG), and a reduction in CB1 receptor expression [10, 12]. These changes may contribute to symptom development, lesion proliferation, and disease progression. Furthermore, cannabis may slow endometriosis progression through effects on angiogenesis [13], apoptosis [14], nerve innervation, cell migration [15], and endometrial hyperproliferation [16], potentially reducing the need for future surgical interventions, assisted reproductive treatments (ART), and other medical therapies. In a recent study of NZ patients self-medicating with medicinal cannabis for endometriosis-associated symptoms, 81% reported reduced pain [17], with similar findings observed internationally [11, 18–20]. The complexities around medicinal cannabis as a legal medicine, illegal and legal recreational drug, has lead to difficulties in policy, stigma and lack of strong clinical trial evidence [21]. Subsequently, people often self administer cannabis illicitly [22].

Medicinal cannabis was legalised in NZ in 2020. However, there is a paucity of scientific evidence on the therapeutic benefits, and available information for patients and prescribers (general practice; GP) across the country. Most GPs have concern around efficacy and safety of products, restrictions, funding, and consequences for their professional reputation [23, 24]. Low-dose CBD has recently been made legally available without prescription (over the counter) in NZ, although no products yet meet the regulatory requirements. This gives weight and urgency to understanding its perceived efficacy and safety. More substantial evidence is required before medicinal cannabis is a widely accepted and legitimised treatment in the NZ medical community.

This small prospective cohort study aimed to explore in a ‘real word’ cohort, the perceived impact of medicinal cannabis at treating pelvic pain and other symptoms in those suffering from endometriosis in Aotearoa and to determine if a larger randomised controlled trial may be warranted.

Methods

Design

This was a small cohort observational study of participants prescribed medicinal cannabis for the first time, for endometriosis related pain. The study received ethical approval by the University of Otago Ethics Committee (H23/026). The study used a mixed methods approach; quantitative measures were completed over three months with an additional qualitative interview at completion (Table 1).

Table 1.

Study design

Timepoint	Data collection
Pre-prescription	Pain Score EHP30
During prescription - Weekly	Pain score
12 week completion	EHP30
Completion (< 3 months post data collection)	Interview

Participants

The study was designed as a ‘real world’ investigation of people’s experiences accessing medicinal cannabis for the first time. Inclusion criteria were: age over 18, surgically or clinically diagnosed endometriosis (clinical assessment either by transvaginal ultrasound or suspected by specialist gynaecologist), never been prescribed medicinal cannabis and not been a regular user of cannabis in the past 3 months. Clinical indications for medicinal cannabis prescription were at the discretion of the clinician, most commonly for chronic pelvic pain that had not responded adequately to conventional therapies, or when other options were poorly tolerated. Some participants also requested medicinal cannabis as an adjunct to their existing management. Participants were excluded if they did not meet any criteria or the consulting clinician deemed contraindicatory, such as pregnancy, mental health concerns or cardiac abnormalities.

Recruitment

The study was advertised through social media platforms (Instagram and Facebook). Eligibility was first screened by the research team via an online questionnaire and follow-up phone call. Participants self-reported a prior diagnosis of endometriosis and were asked to specify whether this was surgically confirmed (laparoscopy/histology) or clinically confirmed (specialist gynaecologist assessment ± transvaginal ultrasound). Potential participants self-engaged with a speciality medical cannabis clinic (Auckland New Zealand) and were required to provide the name of the diagnosing clinician or clinic, and this information was verified by the prescribing clinician prior to prescription. Final confirmation of eligibility, including medical history review and assessment for contraindications, was undertaken by the clinician during the initial consultation. Only participants deemed clinically suitable were prescribed medicinal cannabis and enrolled in the study. People that met the inclusion criteria gave written informed consent to join the study. Participants had consultations with clinicians either in person or via video call. Participants did not receive additional pain science education or support. They were able to continue their other hormone or analgesia medications during the study. Participants received a voucher (Prezzy card) at the completion of the study.

Participants were permitted to continue their usual medical management of endometriosis, including hormonal therapies and analgesic medications, throughout the study period (Supplementary Table 2). These treatments were not standardised or restricted, as the study aimed to reflect real-world prescribing and use of medicinal cannabis.

Quantitative data measurements

Pelvic pain severity

Participants scored their pelvic pain for the past week on a numerical rating scale of 0–10 (0 being no pain, 10 being worst pain imaginable) commonly used for endometriosis and other chronic pain conditions [13]. Pelvic pain was scored in two ways - ‘overall’, and ‘at its worst’, and this data was recorded retrospectively for the last seven days.

Endometriosis Health Profile 30 (EHP-30)

This is a standardised questionnaire for endometriosis [25] which assesses health-related quality of life. EHP30 questionnaires were completed before the prescription commenced and at the end of the 12 weeks.

Adverse events were recorded at follow up appointments by the coordinating nurse, and through the qualitative interviews at the end of the study period.

Weekly pain scores (overall and worst) were recorded directly into REDCap [16] by participants using an online survey format. Symptom impact and EHP-30 surveys were completed via email and documented in Microsoft Excel by the researcher. Descriptive statistics were used to report the mean ± standard deviation and 95% confidence interval (CI) for comparing week-1 and week-12 pelvic pain and total pre and post medicinal cannabis EHP30 scores.

Qualitative data

Participants were invited to interview at the completion of the study. The interviews were conducted between 1 and 3 months of completing the study. The interview schedule and prompt questions were developed for this study by CH and HA (supplementary file 1, table 1). Interviews were conducted over Zoom call and audio were recorded using the zoom record function in addition to hand held recording device. Questions addressed general experiences of endometriosis and pain, administration and dosage of medicinal cannabis, outcomes of medicinal cannabis, barriers and facilitators to using medicinal cannabis. Transcripts were obtained via OtterAI and rechecked for sense. Interviews transcripts were read and re read by at least two researchers in order to generate codes (Supplementary Table 2). Inductive thematic analysis was used to derive themes from the interview transcripts including the use of structured codebooks and consensus coding [26].

Results

Quantitative

A total of 40 participants were recruited and consented to the study. Ten participants dropped out early in the study (lost to follow up; did not make appointments). Two withdrew during the 3-month period (due to pregnancy). Therefore, 28 completed the 3 months in its entirety. No participants had surgery or had used medicinal cannabis in the 3 months prior to engaging with the study. Fifteen participants were prescribed CBD oil alone, and 13 were prescribed CBD oil and flower. The demographic information of participants is presented in Table 2. The mean age of participants was 30 years and ranged from 18 to 46 years. Participants identified as NZ European, Māori, European and other (including Canadian, Indian and Latin American).

Table 2.

Demographics of participants (n = 28)

	N	(%)
Age
18–30	14	(50)
31–50	14	(50)
Ethnicity
NZ European	13	(46)
NZ Māori	5	(18)
European	6	(21)
Other	4	(14)
Type of diagnosis
Surgical	19	(68)
Clinical	9	(32)
Prescription
CBD oil	15	(56)
CBD oil and Flower	13	(44)

The consulting clinicians prescribed CBD oil (oral) with/without flower (Tea, THC) at their discretion (supplementary Table 1). The prescribing doctor prescribed varied dosage, routes of administration and allocation to CBD or CBD and flower groups based on clinical judgement in each case. CBD oil was prescribed at a starting dose of 0.25 ml (equivalent 25 mg CBD) per day and with potential to increase to 50 mg twice daily, and extra doses PRN (50 mg as required). Low THC (15.25%) Flower was prescribed for a subset of participants. Dosage averaged 0.32 mg/day and ranged from 0.05 mg/day to 0.7 mg/day. Participants commenced the initial dose themselves and had additional consultations to increase dosage if required.

Adverse events

One participant reported adverse effects to the CBD oil (nausea), in relation to being allergic to the coconut oil component of the product. Three participants (10.7%) reported headaches that self-resolved, one participant reported fatigue, and one participant reported drowsiness.

Pelvic pain

There was a downward trend of overall and worst pain through the 12-weeks of the study across the whole cohort (Fig. 1A). There was a difference between pain scores for week 1 compared to week 12 with a decrease in ‘overall’ pain from 5.46 ± 1.55 (CI 0.57) to 3.77 ± 2.25 (CI 0.83) and ‘worst’ pain from 7.62 ± 1.51 (CI 0.56) to 5.38 ± 2.69 (CI 1.00) (Fig. 1A). People who were prescribed CBD oil and flower had higher overall and worst pain scores than those who were prescribed just CBD oil (Supplementary Fig. 1A and B).

Fig. 1.

A Mean overall (black) and worst (grey) pain across weeks 1–12 for all participants (n = 28). B EHP-30 scores per domain pre and post medicinal cannabis prescription (n = 28)

Quality of life

Across the whole cohort, there was a substantial decrease in mean total EHP-30 score from 68.77 ± 15.17 (CI 5.61) at baseline to 37.40 ± 16.66 (CI 6.17) after 3 months which indicates improved quality of life. There was a decrease across total, and all EHP-30 domain scores at the end of the 12-week prescription in comparison to the start of the study (Fig. 1B). Score reduction was still observed when split into CBD versus CBD and Flower participant groups, however the scores relating to pain were more pronounced in the CBD oil only group (Supplementary Fig. 2A and B).

Qualitative

Seventeen participants engaged in interviews, between 18.44 min and 42.17 min in length, with an average of time of 29.10 min. After reflecting on their experience, 4 participants (flower and oil) described the outcome as ‘life changing’, 10 participants (5 flower and oil, and 5 oil only) described the outcome as ‘helping to manage pain’ and 3 participants (oil only) described the outcome as ‘no effect’.

The themes were: motivations for seeking medicinal cannabis, using medicinal cannabis, barriers to using medicinal cannabis, and stigma (Table 3).

Table 3.

Themes and subthemes

Theme	Sub theme
Motivations for seeking medicinal Cannabis	Journey through the system
	A toolbox of trial and error
Medicinal cannabis as a medication	Previous knowledge of medicinal cannabis
	Pain & other symptoms
Barriers to medicinal cannabis	Cost
	The complexity of using flower
Medicinal Cannabis stigma	The medical experience
	Friends and family

Theme 1: Motivation for seeking medicinal cannabis

Participants opened the conversation with their endometriosis journey which was important to contextualise their experience, perspective and motivations for seeking medicinal cannabis. As well established in the literature, participants described significant delays to diagnosis and often identified that “looking back, I know that I suffered from it at a young age” (P21). They described difficulties with the health system such as accessing a “stretched [primary care] system” and barriers such as referrals to specialists, funding issues, and being “[sent] from one doctor to the next one”. Many described the impact this had on their social/work life and mental health, and the value of a diagnosis being a “big relief”.

Participants acknowledged the complexity of their pain during course of the 3 months. Pain levels fluctuated not only with menstrual cycles but also with stress, anxiety and concurrent treatments. In weekly pain scores, participants frequently annotated factors such as the onset of menstruation; ‘had day 1 of my period within this week. Was very painful’ or external stress; ‘been a lot happening in our life lately so stress has added to my pain’.

Participants described a variety of treatments they had tried for their endometriosis. An individual and personalised combination of analgesic, contraceptive, and holistic medications as well as lifestyle modifications was used by participants in an attempt to self manage their pain. The following medications were listed by participants: Codeine, Tramadol, Gabapentin, Panadol, Ibuprofen, Diclofenac, Amitriptyline, Morphine, Opioids, Naproxen, contraceptives (IUD, jadelle, depo provera, combined pill), Ketorolac, Protein Pump Inhibitors (omeprazole) and Rizatripan. Often, participants could not remember all the medications they had been prescribed, for example one describing changed “birth control three times” (P1) in one year.

Trialling forms of medications often resulted in worse pain, additional symptoms (headaches, gastrointestinal pain or reflux), weight gain or changes in mental health. Tramadol and Codeine were regularly used by most participants, but with side effects such as nausea, and a ‘zombified’ feeling (P19), and others describing ‘I hate the way tramadol makes me feel’ (P1). Participants did not want to “be reliant on pain medication’ (P15), and others felt the side effects of these medications were often dismissed by healthcare professionals, or worse than the medication itself:

“i was on that for a bit but I gained 30 kgs in six months? and they were like ‘thats normal’ and im like ‘It’s not normal’! But because of all the weight gain I was like, I can’t be on this anymore.” (P1).

“When I was bleeding a lot they gave me some medication to coagulate my my blood – tranxamaic acid. It nearly killed me it was giving me headaches. it was horrible.” (P4).

Participants acknowledged the difficulty in finding medications that ‘work’. They identified that they had tried a combination and range of medications during flare-ups that help manage their symptoms. Participants described that there are “so many management tools” (P15), and that “every treatment is trial and error” (P7). While many participants indicated that they had to manage their own pain and medication use, there was also a desire for holistic, supportive care, hence the seeking of medicinal cannabis as an alternative medication option:

“One of the things with endo is you have all these different approaches for pain, pain management, and management of other symptoms, too. And they’re all coming from different places. And you’re the one who sort of has to synthesize and make sense of them all. Like, I very rarely get any sort of like holistic care. So I think any movement towards that or any just perspective that can be offered about how it might fit in with other things, acknowledging that it’s very individual and patient dependent in terms of the suite of symptoms that we face, but I do think that would be nice. (P6)

Participants believed that enrolling in the study allowed them to access and trial a potential treatment option that they otherwise may not have considered, in a controlled manner. They were happy to add to expanding research on alternative treatments for endometriosis.

Theme 2: Using medicinal cannabis

Most participants had limited knowledge of medicinal cannabis in Aotearoa, and perceptions of the medication were based on previous/historical recreational use. Previous recreational use was spoken of negatively, and “bad experiences” (P21) were recounted, making people “nervous” (P2) or “quite concerned” (P4) whether it would be appropriate for them. Other participants who had heard of medicinal cannabis and were “comfortable with the idea” (P6) were made aware of it (and its legality) by friends or support networks (such as Facebook groups). Almost all participants had not “looked into it” because of the cost, not knowing if they needed a referral or where to find information, or the feeling that they were “doing something illegal”. Other participants noted that they were not aware how to seek a cannabis prescription:

“I knew there were places around New Zealand… but I didn’t know. Like, really where to start” (P16).

Pain & CBD oil

Participants described a variety of treatment effects with using CBD. Participants started on a low dose and most increased as directed by their doctor. Whilst some experienced decreased overall pain, majority of participants noted changes in other aspects of their health, such as sleep and anxiety. Benefits on sleep and anxiety had almost an equal effect on quality of life as reduced pain:

“helped my sleep a lot to start with. And then maybe a month, month and a half until that started helping the pain I think.” (P5).

“I feel pretty confident that the CBD oil is very helpful for me, primarily for sleep. And like anxiety around around the illness. Yeah. I have felt like, my baseline pain has been lower over the last couple of months. And I don’t know if there’s like an inflammatory contribution.”(P6).

Other participants described benefits related to other aspects of life such as work; CBD meant being able to re-enter the workforce “I now have a job interview after three years out” (P20), and for others it meant they were “in such a good place health wise that we’re starting to try to have a baby” (P25). Others described the general benefit CBD has had on their mental health:

“As I started the studies CBD have definitely changed my life in many ways in one is my mental health my moods I can talk without crying” (P4).

“I would say when the pain is bad, the pain is still bad. But it’s not so prominent anymore.” (P20).

A number of participants remarked that they were able to decrease other pain medications during the 3 months due to CBD; one person had been documenting their tramadol usage:

“Did i tell you the numbers?! I had 60 Tramadol before the trial. 60 for each month, and then September, the first month of the trial I had 15. October 10 Tramadol. then November 15” ((P22).

Another was able to decrease anxiety medication:

“normally I’m on Lorazepam for December. It’s like it’s my little Christmas present to myself (little anxiety). So yeah, just I’ve actually been finding that I’m not feeling that way as much”. (P16)

For those who found no benefit from CBD oil, there was an overall feeling of disappointment and uncertainty about whether it “worked”. Most acknowledged the complexity of endometriosis related pain and agreed that “its a real compound effect” alongside sleep, anxiety, nutrition, and other holistic facets. Some participants described “not being sure” about overall pain and noted that the “stronger/sever pain still comes through”. Thus, CBD did not provide benefit for all participants in this study, with effect ranging from life changing to none at all.

Pain & flower

Participants found the flower to be most useful for flare ups when people “couldn’t deal” with severe pain and for some it was the preferred medication over prescribed analgesics. Some participants were able to stop opioids entirely, and others used flower in very small quantities, describing it as “Little bits here and there when I need it” (P20).

The main challenge with flower was that participants found the dosage hard to get right. Usually, they had had too much and felt the “stoned’ effects which was not desired. Some participants used a vape to administer flower; there was an idea that vaping flower should result in “a cloud of smoke” based on nicotine vapes, and therefore some participants did not think the vape worked as this was not occurring. Rather, it had worked and they had inhaled too much flower. However, participants compared the treatment effect of flower to that of tramadol, which to them had a worse outcome:

“I felt so much more relaxed in my body, it was better than tramadol in that way like tramadol took away the pain but it could still feel stuff and couch locked but with the cannabis I was able to vacuum the house do the dishes. I could do cooking.” (P22).

Theme 3: Barriers to using medicinal cannabis

Cost

Every participant identified cost as the main barrier to medicinal cannabis and described it as ‘unattainable’. This included oil, flower, and the vape. Given the fact that CBD oil takes time to have benefits, participants noted this to be a particular issue if you are self-funding; “And what about if it doesn’t work, but after a few weeks you realise that the change is there” (P4).“It’s a heap of money if you… suddenly don’t find that it’s working”. (P16)

Some participants also recognised that while they were in a position to self-fund medication, the cost was still a prohibitor, and thereby they questioned equity in accessing this sort of treatment. Participants in jobs which were described as “with a decent salary” (P6) still felt the cost was prohibitive. Others felt that the quantity of flower was more than they needed, and would instead prefer a smaller, more cost-effective quantity.

However, other participants were open to trying new/alternatives treatments and were willing to “spend money and invest in [my] health” (P18). Yet, this is not a position that all people can take, suggesting cost acts as a barrier for people accessing medicinal cannabis in Aotearoa.

Complexities of using flower

Whilst flower was able to help with severe pain flare ups for some participants, there were multiple barriers to using flower. Driving and ‘being straight’ (no ‘high’ effects) were factors that meant that people would not use it often or during the day “I basically can only have it at night because I can’t drive for six hours and I can’t actually ‘person’ with it all” (P16). This experience was shared across the dataset:

My general personal rule is just going to be that the vape stays at home. And if my pain is bad enough that I’m needing it, I probably need to go home anyway. Definitely get a certain level of impairment and don’t want to be trying to deal with it and do my work at the same time. (P20).

However, for one participant, vaping flower was the one medication that allowed her to leave the house and attend social events, with the support for her friends.

I took it everywhere with me, it enabled me to actually like leave the house for a couple hours at a time when it was really nice to have that freedom to go out. Like went out to dinner with my friends. And normally I’ve been only like last an hour, but I went outside and had a little vape, because I could sit and enjoy like, dinner and coffee and stuff after dinner and yea. i vaped a lot! So like if I was vaping then they were like that’s fine. We could just pick you up.(P6).

Other participants however felt that sharing their use of flower could be problematic, and many did not discuss medicinal cannabis (flower) in their workplace. This was because they were unsure about the regulations that would apply to them; “i dont know if that applies to us or not” (P18). Further, other participants noted the complexity of being a medicinal cannabis user while being a parent:

“I don’t want people to think I’m getting stoned around the kids if they’re over for playdate…I don’t want her to see me vaping either. She already saw that I had it and she’s eight and gave me a stern lecture on how bad it is. I had to explained that mommy’s tummy gets really sore and that the medicine helps.”(P16).

Less commonly, participants also discussed the barrier of using flower in the form of a vape due to past smoking habits. They were worried that using flower in a vape could trigger these addictive habits:

“The reason I was scared to have a vape was because i, I had quit smoking in 2020. And but I switched to vaping. And then I’ve quit vaping and I was like, Damn, I’m having this device again. Is there gonna be like that? trigger? but When I got it, it didn’t feel like that.” (P22).

Theme 4: Medicinal cannabis stigma

The medical experience

Most participants were ‘intimidated’, felt like they were ‘a big stoner’ and ‘shy’ for their first consultation to receive medicinal cannabis with the prescribing clinic. However, many participants remarked that they became comfortable and the conversation was based on informed shared decision making, the knowledge of the doctor, and response for them as an autonomous person. One participant described that they perceived their prescribing doctor as different to a ‘normal’ doctor:

“I found that like, really intimidating at first, just not having any idea of like, what to expect or? I don’t know, it’s a little bit different to like a normal doctor.” (P19).

Others explained that despite the prescribing experience being positive, it was “a weird thing to be prescribed” (P22), and that it was easier than they thought it would be.

When asked about their relationships and conversations around medicinal cannabis with their primary healthcare provider (GP), participants were worried they would not listen or be told ‘you shouldnt be doing this’(P1). Less commonly, some participants felt their regular GP was “very open and empathetic” (P25). However, many had broached the topic previously and not had any luck with receiving a prescription as the doctor was not comfortable:

“I have actually asked a couple of different doctors that I’ve seen before, like, oh, you know, I’ve heard about CBDs and they kind of just say, Oh, I don’t know anything about it. So you know, and they’re not like kind of too keen to prescribe it.” (P21).

“I think I had mentioned it to her in the past, before this trial. And she was like, oh, no, no, we don’t, you don’t need to go down that path or whatever. And you’re just like, Oh, come on. Knowing my history and things you would think you would just offer your patient anything!” (P7).

Friends and family

Participants found that when they explained how medicinal cannabis worked, and provided information to friends and family, that there was more understanding and breaking down of stigma. Some participants also noted that their family and friends were understanding due to the effects of endometriosis:

“They also are very aware of the struggles of Endo. And so kind of anything that’s going to help or might help. You know, quite on board.” (P13).

“It is like for all of my family, saw how miserable I was before, and see how much of a difference it’s made to my life. And therefore it’s like, well, why wouldn’t you support this? Absolutely.” (P20).

Other participants reflected on how their medicinal cannabis use was impacting how their family considered their own health. There was knowledge sharing between parents or other older family members, who were empowered to look into medicinal cannabis for their conditions such as arthritis or encephalitis. One participant said: “My mum started using it too” (P10). In contrast, there was concern around drug seeking, addiction or ‘gateway’ use from other participants’ older family members. One participant noted that she was somewhat worried about her safety having ‘drugs’ in the house and family members stealing it. Thus, there was a dichotomy of experiences in regard to friends and family.

The role of culture in medicinal cannabis acceptance was also considered. One participant commented that her Māori whanau supported her as they are more open and understanding to a natural medication in comparison to tramadol.

Discussion

This was a small cohort study where participants were followed up over 12 weeks to observe and collect data on pelvic pain, symptom impacts and health-related quality of life in the context of starting a new medicinal cannabis prescription. Our findings suggest that usage of medicinal cannabis had limited adverse events and resulted in a decrease in pain and improved quality of life over a 12-week period.

It is important to acknowledge the changing landscape of medicinal cannabis, legalisation, policy on administration and dosage, and patient autonomy on accessing a range of products or dosage administration. The increased use of medicinal cannabis on a global scale has shown benefit, for example for conditions such as epilepsy, multiple sclerosis or cancer [27]. However there is concern for potential adverse events such as cannabis use disorders or drug interactions [28], highlighting the need for careful consideration around treatment monitoring and public health messaging.

In this study, most participants had an interest, but limited knowledge of medicinal cannabis prior to its use. A lack of accessible, evidence based information around medicinal cannabis use, dosage and potential benefits has been well documented across both patient and health professional communities [29–31]. Many participants had pre-conceived negative perceptions about cannabis, which aligns with health concerns and stigma often associated with its use [32]. However, as the study progressed, participants’ perceptions shifted positively as they felt more comfortable with the prescription process, and experienced some benefits of medicinal cannabis as part of their pain management ‘toolkit’.

The complexity of using medicinal cannabis in certain aspects of daily life, particularly in relation to work and driving, was another theme that emerged. This has been highlighted in other research on medicinal cannabis use, where concerns about impairment and its effects on professional responsibilities or driving were identified as significant barriers [31]. The impact on daily functioning, including driving laws, continues to be a critical area for further investigation, especially as legal frameworks surrounding medicinal cannabis use evolve [33, 34].

Several participants in this study reported previous use of opioid-based analgesics such as tramadol, which provided limited or inconsistent relief and were often accompanied by undesirable side effects including nausea, dizziness, and fatigue. In contrast, CBD was perceived as a gentler alternative that offered effective symptom relief without the sedative or cognitively impairing effects commonly associated with opioids. These findings echo prior research suggesting that cannabinoids, particularly CBD, may provide analgesic benefits with a more favorable side-effect profile than traditional opioids [35]. However, it is important that prescribers discuss the side effect of feeling ‘high’ and that dosage is adjust on a case by case basis, including mode of consumption and product potency [36].

Cost (and size of flower product) was identified as the primary barrier to access, which mirrors findings from numerous studies examining the financial constraints associated with medicinal cannabis [37–39]. High out-of-pocket costs remain a significant challenge for many patients, and financial accessibility could play a crucial role in determining who benefits most from this treatment option. This finding highlights the need for further advocacy and policy change to improve insurance coverage and reduce the economic burden on patients seeking medicinal cannabis.

Finally, knowledge sharing among friends and family was found to be a positive influence in participants’ decisions and experience of medicinal cannabis. This supports previous findings that social networks play a key role in the dissemination of information about cannabis. The sharing of experiences, particularly from those with chronic pain, can enhance confidence and support informed decision-making regarding medicinal cannabis use particularly when evidence based information is not readily accessible. However, online platforms disseminate potentially bias and anecdotal information [40]. Furthermore, endometriosis has a history of delayed diagnosis, medical gaslighting and holistic unmet need as illustrated in theme 1 (motivation for seeking medicinal cannabis). Therefore, people with this condition are more likely to seek control over their treatment and explore alternative therapies [41].

Endometriosis pain management is often complex and individualized. Not all participants had a positive experience/benefits from this treatment and research efforts should focus on mechanisms of action and markers of treatment response. Pelvic pain severity was not separated into dysmenorrhea and non-cyclical pelvic pain. While this distinction would have been valuable, it remains a common limitation across many endometriosis clinical trials [42], and even recent trial guidelines do not mandate it [43]. Nonetheless, future research should consider incorporating these distinctions to enable more nuanced analysis.

The strength of this study lies in its ‘real word’ design and in-depth qualitative analysis of participants’ experiences of using medicinal cannabis for the first time to treat endometriosis-related pain. However, the study design has limitations and all findings must be interpreted in light of these. Most participants completed the interview between 1 and 2 months post-study completion which may introduce recall bias; this time delay was caused by the interviews scheduled after the Christmas holiday period according to availability of participants. The study was limited in its sample size and in its potential for selection bias. Participants were recruited through social media and self-selected into the study, which may have favoured individuals already motivated to seek cannabis-based treatments or holding positive expectations of benefit, and those recruited via social media are likely to be more unwell than those recruited through other means. In addition, the observational cohort design means that non-specific effects and expectancy effects cannot be excluded as contributing to some of the improvements observed in pain and quality-of-life measures and that these are not considered causative. In addition, pain was not analysed in relation to phase of menstrual cycle. Most participants had a complex history of hormonal and pain medications (supplementary Table 2), and surgery (including hysterectomies) and therefore it was not appropriate to subgroup the data. However overall, our qualitative analysis supports some benefits of CBD on pain and sleep for most participants. In addition, it is important to note the clinically relevant changes in EHP-30 scores; the substantial decrease across all EHP-30 domains surpass the clinically relevant threshold (3.2–17.5) for minimally important differences and index of responsiveness [44]. Together this highlights the importance for future randomised, placebo-controlled trials to validate the therapeutic potential of medicinal cannabis in endometriosis.

Comparison of outcomes between those taking CBD oil versus CBD oil and flower was exploratory in nature. For example, those on CBD oil alone appeared to have greater improvements in pelvic pain, symptom impact and health-related quality of life scores compared to those prescribed CBD oil and flower. A possible explanation for this, supported by the qualitative data, is that those with more severe symptoms at the beginning of the study were prescribed flower as well as oil, and as such they did not experience such marked improvements as CBD oil only. Due to the observational nature of the study, the exact cannabis dosage received varied between participants. This is particularly noted with dried flower as it was prescribed for oral consumption (tea) with few choosing to use a vaporiser.

Due to the small sample size and subsequent split of the group between those prescribed CBD and CBD with Flower, this study was inadequately powered for further statistical analysis. However, it provides novel preliminary data to guide sample size calculations for future clinical trials, including intention to treat designs, in Aotearoa New Zealand.

Conclusion

This was the first prospective cohort study of medicinal cannabis for Endometriosis related pain in Aotearoa. Some participants in this study percieved reduced pain measurements and increased quality of life. Further large-scale studies and clinical trials are urgently needed. The complexities surrounding knowledge, accessibility, and daily life integration highlight the need for ongoing education, improved policy, and further clinical research to optimize the use of medicinal cannabis in chronic pain management. Widespread education around the use of medicinal cannabis is welcomed; if it can be offered by and discussed with a trusted healthcare provider, the stigma surrounding it as a legitimate form of treatment may decrease.

Authors’ contributions

All authors contributed to the study design, data interpretation and manuscript preparation. CH recruited participants, collected and analysed data (quantative and qualitative), wrote manuscript and managed research team. LC analysed and interpreted quantative data. HA analysed and interpreted qualitative data. JS, AM, AS and AW interpreted results and edited manuscript. MA advised on study design, data analysis, data interpretation, and manuscript preparation.

Funding

Financial support for this study was provided by EndoWarriors Aotearoa and Medleaf Therapeutics NZ (participant koha vouchers), and Helius Therapeutics NZ (CBD oil).

Data availability

The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request.

Declarations

Ethics approval and consent to participate

This study adhered to the declaration of Helsinki and was approved by Otago Health Ethics Committee, #H23/026. All participants provide free and informed written consent.

Consent for publication

No individual data is submitted for publication, all data is de-identified.

Competing interests

Medleaf Therapeutics and Helius Therapeutics contributed funding to support this project. Medleaf Therapeutics partially funded participant vouchers ($2,000 total). Helius provided subsidised CBD oil to Cannaplus for participant prescriptions. Both companies were not in-volved in study design, analysis or manuscript preparation. JS Is currently employed at Australian Natural Therapeutics Group and formerly sat on the scientific advisory board for BioCeuticals. JS also sits on the board of the Australian Medic-inal Cannabis Association (pro bono) and the steering committee of Cannabis Clinicians Australia (pro bono).MA has received funds from the Victorian Government, philanthropic donors (Wilson Foundation), and industry partners (Cannim, OzMedicannGroup) for research related to medicinal cannabis, outside the submitted work. He is also a scientific advisory board member for Evolv Health. He is a guest editor for the special edition of BMC complementary medicine and therapy - Advances in cannabis and cannabinoid research.