Uterine fibroids represent the most common tumour in women; this is a monoclonal tumour consisting of an abundance of extracellular matrices that bury disordered uterine smooth muscle cells . The incidence is estimated to be 20–40% in women during their reproductive years, and there is extreme heterogeneity between fibroid size, location, composition, and symptomatology . For example, patients can experience a singular dominant fibroid or a cluster of smaller fibroids.
Whilst these tumours are almost always benign and mostly asymptomatic, women who experience the symptoms of uterine fibroids endure challenging clinical manifestations. These include excessive uterine bleeding, anaemia, defective embryo implantation, recurrent pregnancy loss, preterm labour, obstruction of labour, pelvic discomfort, urinary incontinency, and may mimic or mask malignant tumours .
Imaging techniques are used to diagnose patients with uterine fibroids, and accurately assess the size, number, and location of the growths . These include:
- Saline-infusion sonography
- Magnetic resonance imaging (MRI)
In asymptomatic people, uterine fibroids can be found during a pelvic examination or through imaging .
Many patients with uterine fibroids are asymptomatic and therefore remain undiagnosed. It is estimated that 7 to 8 in every 10 women will develop a uterine fibroid by the time they reach 50 years of age, yet only 20–40% of women will receive a diagnosis.
What causes uterine fibroids?
Studies suggest that uterine fibroids originate from the transformation of a singular stem cell in the myometrium (the muscular wall of the uterus) into a tumour-initiating cell . The origin of this transformation has been proposed to be genomic instability, inflammatory microenvironment, cell fusion, lateral gene transfer, or environmental factors . Clonal tumour growth is then triggered through endocrine, autocrine, and paracrine growth factors and hormone receptor signalling (i.e., it is an oestrogen- and progesterone-dependent process). Uterine fibroid size can cause the uterus to expand to the size reached at 6 or 7 months of pregnancy .
What treatments are available for uterine fibroids?
Treatment of uterine fibroids is dependent on the tumour size and location, age, symptoms, desire to preserve fertility, and access to therapy. The primary treatment goals are to relieve symptoms, reduce fibroid size, maintain fertility (if desired), and avoid harm . There are various treatment options available for various patient types depending on if they are symptomatic or asymptomatic; premenopausal or postmenopausal; with a desire to keep their uterus or fertility, or without this desire.
Broadly, these treatments can be characterised as:
- Medicinal therapies
- Surgical therapies
Medicinal therapies for uterine fibroids
Medicinal therapies include hormonal contraceptives, antifibrinolytic agents (e.g., tranexamic acid), non-steroidal anti-inflammatory drugs, hormone therapy, etc. The main aim of these therapies is to reduce menstrual blood loss, improve pain relief, and reduce fibroid volume. These therapies allow fertility to be preserved; the effects are often temporary and are followed by surgical therapies which can result in infertility .
Surgical therapies for uterine fibroids
Surgical therapies include hysterectomies, which provide a definitive cure for uterine fibroids through the removal of the uterus. Another option is a myomectomy which involves surgical removal of the uterine fibroids themselves rather than the entire uterus. Similarly, myolysis is a minimally invasive surgical procedure that destroys fibroids using focused energy delivery systems. Hysterectomies result in infertility, whereas myomectomies and myolysis provide the possibility of maintaining fertility (although this is not guaranteed) .
Do uterine fibroids affect reproductive potential?
The actual effect of uterine fibroids on fertility is neither completely known nor understood. They have adverse effects on reproduction as they are associated with infertility, early pregnancy complications, and adverse obstetric outcomes . There are numerous proposed mechanisms by which this impairment could arise:
- Local anatomy alteration
- Functional changes
- Paracrine molecular effects
- Endocrine mechanisms
These mechanisms could present simultaneously and to varying degrees, leading to impaired gamete transport and reduced embryo implantation ability. This may be due to the creation of a hostile environment and a subsequent reduction in reproductive potential .
In addition to the effect that the presence of the tumour can have on fertility, there is a significant discussion to be had concerning the effect of tumour removal. Surgical excision of uterine fibroids is associated with myometrial trauma and functional consequences . Gynaecologists and specialist clinicians are expected to answer the question: Will fertility return to the patient after fibroid excision?
The answer to this question is complicated and must consider the size, number, and location of the fibroid(s), the expected impact of the tumour on fertility, the effectiveness of the surgical intervention, and additional clinical indications. As stated, the extent to which fertility is affected is not completely understood, however, evidence suggests that surgical excision of uterine fibroids is associated with improved fertility potential and in vitro fertilisation (IVF) outcome (depending on their location) . Due to the experienced surgical trauma, this cannot be guaranteed for all patients.
A hysterectomy is the only permanent intervention to treat uterine fibroids, but women are left having to decide between having surgery to address their life-altering symptoms or becoming pregnant. Moreover, if they have the option of excising just the fibroids rather than their whole uterus, this can still have a significant impact on their ability to conceive. It seems that, as they often are, women are left to choose between their personal health or motherhood.
Racial inequities with uterine fibroids
Black women are disproportionately burdened by uterine fibroids with a substantially higher incidence rate than any other racial or ethnic group . They have a three-fold higher risk of fibroids, an earlier age of onset, and more severe symptoms than White women, accompanied by a higher risk of complications with surgical treatment . Additionally, the tumours in older White women grow slower than those in older Black women (2% vs 15% growth rate respectively) . Furthermore, these tumours in White women demonstrated a significant decline in growth rate with age, although this was not observed with the tumours in Black women .
The drivers of these racial disparities are poorly understood. Genetic and molecular differences between the fibroids have not been found to explain the increased burden on Black women . It has been suggested that this disparity could come from chemical and nonchemical stressors related to inequality, or lifestyle choices such as diet and commercial product use. For example, hair relaxers are popularly used by Black women, and these have been linked to an increased risk of uterine fibroids . (Moreover, this represents a larger issue of influencing ethnic minority groups to conform to Eurocentric beauty standards and showcases the health implications that can arise as a result).
There is a pressing need to examine why Black women are being burdened by uterine fibroids at a disproportional rate. Black women are more likely to undergo hysterectomies vs White women. Black women are more likely to undergo open, abdominal surgeries than minimally invasive procedures, which in turn increases the risk of reproductive dysfunction . However, Black women are the least likely to access infertility services in the US and the UK. Moreover, there are countless reported cases of poor patient-doctor interactions, delayed diagnoses, and limited offered treatment options reported by Black women .
Why has this not been addressed?
There are inherent biases within biomedical research – gynaecological research generally prioritises White women. Marginalised groups must be centred in future studies, especially when addressing research areas that are specifically associated with these groups. Whilst there are studies investigating the relationship Between Black women and uterine fibroids, clearly, more research is required.
There are many unanswered questions surrounding uterine fibroids:
- What are the dietary, stress, and environmental influences?
- Are there more techniques available for diagnosis that consider the surrounding tissue?
- Is there a way to remove the tumours and confidently preserve fertility?
- Why are Black women disproportionally affected?
Whilst technically a benign tumour, a uterine fibroid diagnosis can be life-changing and challenging in incomprehensible ways. The symptoms experienced can be debilitating in the form of pelvic discomfort and excessive uterine bleeding. They can have consequential health implications such as anaemia, which can, in turn, trigger further symptoms such as restless leg syndrome. The risk of infertility as a result of uterine fibroids can challenge a patient’s life plans and as a consequence severely impact their mental health.
We are fortunate to live in a time when there are minimally invasive treatment options. Gone are the days when the only option was a hysterectomy. Research has come a long way to address this women’s health issue, but there is a long way still to go. Despite being the most common tumour in women, knowledge about uterine fibroids remains very limited.
Does this remind you of other women’s health issues?
To learn more, please visit: http://www.britishfibroidtrust.org.uk
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