Women with endometriosis reported less pain and better sleep after taking medical cannabis, with improvements lasting for two years in a UK study.

Researchers cautioned that the findings do not prove medical cannabis caused the improvements because the study had no control group and participants received different products and doses.

The observational study followed 101 women prescribed cannabis-based medicines and also recorded improvements in anxiety, quality of life and the effect of pain on daily activities.

The women were followed through the UK Medical Cannabis Registry and completed questionnaires before treatment and after one, three, six, 12, 18 and 24 months.

Pain measures improved at every follow-up point, while improvements in sleep, anxiety and overall quality of life continued throughout the two-year period.

The study also recorded a reduction in prescribed opioid use. Average use fell from the equivalent of 19.9mg of morphine a day at the start of the study to 14.8mg after two years.

Among the 46 participants prescribed opioids at some point during the study, 12, around 26 per cent, recorded what researchers considered a clinically meaningful reduction by 24 months.

Most participants were prescribed cannabis oil or a combination of oil and dried cannabis flower. At the start of the study, 33 received oil alone, 60 received flower alongside oil and eight received flower alone.

Eighteen of the 101 women reported 165 adverse events during the study, around half of which researchers classed as mild.

Fatigue, lethargy and headaches were the most commonly reported adverse events.

The authors said no randomised controlled trials have specifically examined cannabis-based medicines for endometriosis-associated pain and called for further trials to establish effectiveness and safety.

Previous research has also suggested some people with endometriosis use cannabis to manage symptoms, although much of the evidence has come from surveys and observational studies.

A 2024 survey of 912 people with endometriosis in Germany, Austria and Switzerland found that 114 reported using cannabis. Among those users, 91 per cent reported improved sleep, 90 per cent reported improvements in menstrual pain and 80 per cent in non-cyclical pelvic pain.

A separate Phase 2 trial is now examining a CBD oral solution in up to 100 women with endometriosis-associated pain in Scotland.

The ENDOCAN trial, led by Dr Lucy Whitaker alongside Professors Andrew Horne and Philippa Saunders at the University of Edinburgh, is double-blind and placebo-controlled.

Participants are being randomly assigned to receive either Ananda Pharma’s MRX1 CBD oral solution or a placebo for 12 weeks. The study is designed to provide stronger evidence on whether CBD itself can reduce endometriosis-associated pain.

A UK study will build a menstrual fluid biobank to help women get faster, better treatment for heavy periods.

Thousands of participants will provide menstrual fluid samples over three cycles using specially designed period pads. They will also use a daily tracking app and complete detailed questionnaires.

Researchers from the Universities of Exeter and Bristol will work with participants from two UK birth cohort studies, Children of the 90s and Born in Bradford.

Professor Gemma Sharp, of the University of Exeter, said that the study is set to be a ‘real game-changer’ for menstrual health research.

Sharp said: “We know that menstrual health is a key indicator of overall health, but a lack of high-quality data means it remains poorly understood and under-supported in healthcare.

“We also know that heavy periods can affect many aspects of daily life – for example, our recent research revealed an association between heavy periods, school attendance and lower GCSE attainment – so we urgently need new ways to support the millions of women affected by heavy periods more promptly and effectively.”

The CycleTrack study aims to create the world’s largest menstrual fluid biobank for people in their mid-30s.

By combining these samples with long-term health and genetic data, researchers hope to identify biological signals linked to differences in periods and related conditions.

Researchers hope the findings could support earlier diagnosis, better care plans and tools to identify risks including iron deficiency.

The study is part of The Missed Vital Sign, a programme led by Wellcome Leap that contributes to a broader global effort to reduce the time it takes a woman to receive effective treatment for heavy menstrual bleeding from five years to five months.

Up to 50 per cent of women worldwide experience heavy periods, which can significantly affect physical, emotional and social wellbeing.

Researchers say the work could also improve understanding of menstrual health more broadly and help inform future school and workplace guidance.

Australia’s drug advisory committee has recommended wider funding of triptorelin for women with breast cancer or endometriosis.

The recommendation comes after AstraZeneca announced plans to remove Zoladex from the market, risking leaving more than 7,500 women with breast cancer without an alternative treatment.

Both medicines block the release of oestrogen and testosterone and can be used as part of treatment, or for fertility preservation, in some forms of cancer.

The Pharmaceutical Benefits Advisory Committee met urgently in July and recommended making triptorelin unrestricted under the Pharmaceutical Benefits Scheme (PBS), which would mean it was funded for all uses.

The drug has been listed on the PBS for prostate cancer since 2006.

Triptorelin and Zoladex can also be used to treat endometriosis and to block puberty for either precocious puberty or gender-affirming care.

Vicki Durston, director of policy and advocacy at Breast Cancer Network Australia, described the recommendation as “a significant step forward” and said access to the medicine could mean the difference between life and death for some patients.

She said some women had already chosen to have their ovaries removed because of uncertainty over Zoladex supplies.

Marilla Druitt, Victorian state chair of the Royal Australian and New Zealand College of Obstetricians and Gynaecologists, said it remained unclear whether triptorelin would work exactly the same way as Zoladex, but the recommendation was likely to be positive for patients with endometriosis and pelvic pain.

She said: “I’m glad we’ve got an alternative.”

“That’s fantastic, and it remains to be seen whether or not it will be as good, but pain is so complex, pain is a really hard thing to study because it’s got so many contributors.”

Druitt said further research would be needed after the medicine was introduced.

If accepted by the federal government, the recommendation would also allow PBS funding of triptorelin for puberty suppression in precocious puberty and gender-affirming care.

This would make gender-affirming care federally funded through the PBS for the first time and would remove a financial barrier for transgender children in Queensland and the Northern Territory.

Stuart Aitken, medical director of Gender Health Australia, said the recommendation had sparked “absolute joy” among his patients.

He said: “It takes away a huge barrier to accessing evidence-based care.”

“It means that the ban has a very limited effect.”