To review the available literature on the effect of cannabis-based products on the
female reproductive system and establish if there is any evidence that they benefit
or harm patients with endometriosis and therefore if there is sufficient evidence
to recommend them.
An electronic-based search was performed in PubMed, Embase and the Cochrane Database.
Reference lists of articles retrieved were reviewed and a grey literature search was
Methods of Study Selection
The original database search yielded 264 articles from PubMed, Embase and the Cochrane
Database, of which forty-one were included. One hundred and sixty-one studies relating
to gynaecological malignancy, conditions unrelated to endometriosis or therapies unrelated
to cannabis-based products were excluded. Twelve articles were included from a grey
literature search and review of references.
The majority of available evidence is from laboratory studies aiming to simulate the
effects of cannabis-based products on preclinical endometriosis models. Some show
evidence of benefit with cannabis-based products. However, results are conflicting
and the impact in humans cannot necessarily be extrapolated from this data. Few studies
exist looking at the effect of cannabis or its derived products in women with endometriosis
– the majority are in the form of surveys and are affected by bias. National guidance
was also reviewed: at present this dictates that cannabis-based products can only
be prescribed for conditions where there is clear published evidence of benefit and
only when all other treatment options have been exhausted.
Current treatment options for endometriosis often affect fertility and/or have undesirable
side effects that impede long-term management. Cannabis-based products have been suggested
as a novel therapeutic option that may circumvent these issues. However, there is
a paucity of well-designed, robust studies and randomised controlled trials looking
at their use in the treatment of endometriosis. In addition, cannabis use has a potential
for harm in the long term; with a possible association with ‘cannabis use disorder’,
psychosis and mood disturbances. At present, national guidance cannot recommend cannabis-based
products to patients in the UK due to lack of clear evidence of benefit. More comprehensive
research into the impact of endocannabinoids in the context of endometriosis is required
before their use can be recommended or prescribed.