Uterine leiomyomas, otherwise commonly known as fibroids, are non-cancerous masses that develop in the uterus and its adjacent regions. They are the most frequently occurring pelvic tumours in women and are composed of fibrous connective tissue and smooth muscle cells.1 While some women can be asymptomatic, common symptoms of uterine fibroids include lower back pain, pain during intercourse, and prolonged menstrual cycles. Fibroids can also lead to other complications such as infertility and incomplete or failed pregnancies.
Based on their type and location, fibroids can be categorised as intramural (develop in the thick uterine wall), submucosal (develop below the lining of the uterine wall), subserosal (present in the outer uterine wall), intracavity (located in the uterine cavity), and cervical (develop in the cervix).
It is important to note that while fibroids, in most cases, do not mature into cancer, they still pose a heavy burden on the reproductive well-being of women assigned female at birth (AFAB). They account for approximately 40-60% of the total hysterectomies performed and 29% of hospitalisations.1
Risk factors are typically classified as modifiable and non-modifiable. In the case of uterine fibroids, some examples of non-modifiable risk factors include age, hormone levels, race, and genetics.1 Modifiable risk factors, on the other hand, include diet, alcohol and tobacco consumption, and fitness levels.1
Uterine fibroids do not occur before puberty; however, it is well-documented that the risk associated with fibroids is directly proportional to age. This risk reaches a peak at 50 years of age and decreases with the onset of menopause.1
The risk of fibroids is 2-3 times higher in women of African origin than in those with Asian, Hispanic, or White heritage.1 Early-onset leiomyomas were reported in pregnant women of Black origin rather than in those of White origin.1 In addition, Black women are also 2.4 times likely to undergo a hysterectomy and often display fibroids of larger size and higher severity.1
Estrogen and progesterone, the main reproductive hormones in women AFAB, significantly influence leiomyoma formation. Studies have highlighted that progesterone signalling can favour tumour growth and development.1 Furthermore, this cellular activity is sustained due to an estrogen-mediated increase in cell responsiveness to progesterone.1
Chromosomal anomalies and point mutations have been observed in important regulatory genes associated with uterine leiomyoma aetiology. For instance, the upregulation of the genes HMGA2 and MED12 are linked to tumour development and an increase in collagen and extracellular matrix, respectively.1 Additionally, Reed’s syndrome, which occurs as a result of a mutation on chromosome 1, causes a genetic predisposition to uterine fibroids along with renal cancer.1
While there are only a few studies documenting the effect of physical activity on fibroids, results show that regularly active women are at a lower risk for developing fibroids when compared to women who do not exercise.1 It is also well-known that diet and fitness levels are closely linked; therefore, the excessive consumption of red meat has been associated with a 1.3-1.7-fold increase in the risk of fibroids.
Other lifestyle factors such as alcohol, tobacco, and caffeine consumption can influence leiomyoma development, although these results have, so far, been inconclusive and mixed. For instance, some studies describe a direct relationship between caffeine consumption and fibroid risk, while some studies report no significant association of any kind.1
In asymptomatic women, fibroids are often detected incidentally during a clinical examination. The primary method of detection is by performing an ultrasound - both transvaginal and abdominal ultrasounds are used. Transvaginal ultrasounds display a sensitivity range of 90-99%, making them extremely efficient at detecting fibroids.2
A hysteroscopy is performed by inserting a hysteroscope into the uterus. As it can be a painful and uncomfortable procedure, taking a painkiller is often recommended. Hysteroscopies are efficient at identifying and detecting submucosal myomas.2
A laparoscopy involves the use of a laparoscope to examine the tissue and organs within the abdomen. As this method is quite invasive, anaesthesia is provided.
A sonohysterography or a sonohysterogram is used to examine the uterus with the help of sound waves. A transducer that emits sound waves is typically inserted into the vagina to generate images of the uterus for a clear examination. Sonohysterograms are also used in conjunction with ultrasounds and hysteroscopies to enhance the detection of submucosal myomas.2
Tobacco consumption can have harmful effects on all physiological and biochemical processes of the body. It is most commonly consumed in the form of cigarettes and significantly increases the risk of stroke, heart disease, cancer, infertility, and other health issues.
The effects of smoking on reproductive health are well-documented. In those AFAB, smoking can lead to delayed pregnancies, premature births, and stillbirths.3 The implications of smoking during pregnancy are high, potentially causing low birth weights, congenital abnormalities, and infertility.3 Women who smoke are more likely to reach menopause 1-4 years earlier than those who do not smoke.3
Approximately 4000 harmful chemicals are present in cigarette smoke, all of which act on different parts of the female reproductive system.3 The effects of smoking on the ovary and oviduct occur in the form of early menopause, poor oocyte quality, and an increased risk of ectopic pregnancies.3 In the uterus, this can cause delayed implantation and hormonal fluctuations. The ability of the ovary to release a healthy ovum is weakened by about 20% in women who smoke.3 As a consequence, ovulation is impacted, as smoking can damage oocyte health and lower the number of healthy eggs in the ovaries.3 Delays in conception are also observed, with smokers reporting a 54% increase in the delay associated with achieving conception.3
To date, there has been no conclusive evidence about the specific relationship between smoking and leiomyoma development. What we do know is that smoking affects endocrine hormone levels - it lowers the level of circulating estrogen by impairing estrogen production.4 Different results have been obtained from studies conducted in different parts of the world. For instance, a study conducted in China reported a direct relationship between smoking and fibroid risk in White women and not in women of African-American origin.4 In another study on perimenopausal women, researchers observed an increase in the risk of developing late-onset fibroids in women who were environmentally exposed to tobacco smoke.5 These results, however, did not apply to those who were active smokers at the time of the study. In the same study, women who were former smokers and exposed to high levels of tobacco smoke were twice as likely to develop fibroids as those who were unexposed former smokers.5
Few studies have also reported that cigarette smoking had a protective effect on fibroid development in ever smokers.4 In another cohort study, active smoking was found not to affect leiomyomas.4
It is crucial to bear in mind that these studies often exhibit lots of heterogeneity in their parameters, study design, and methods of analysis. These parameters include, but are not limited to, ethnicity, age, number of participants, duration of smoking habits, and frequency of smoking habits.
The best strategy to treat fibroids must be decided based on the patient’s symptoms, age, background, and the size and location of the leiomyoma. Pharmacological avenues of treatment are non-invasive and involve the usage of non-steroidal anti-inflammatory drugs (NSAIDs), oral contraceptives, intrauterine devices (IUDs) like Mirena, and progesterone receptor modulators.2 Most of these treatments preserve fertility and reduce fibroid volume and fibroid-associated blood loss.2
Surgical treatment options include hysterectomy (surgical removal of the uterus), myomectomy (surgical removal of the tumour), guided ultrasound surgery (involves the use of ultrasound waves to destroy fibroids), and uterine artery embolisation (uterine vasculature is radiologically obstructed to stop tumour growth).2 While myoma recurrence is a possibility, it is worth noting that this can vary depending on many factors. Additionally, procedures such as hysterectomy do not preserve fertility, and ultrasound surgery may cause heavy menstruation post-surgery.2 Therefore, while surgical treatments do alleviate fibroid symptoms, the choice of treatment must be made after careful consideration.
