Uterine fibroids are benign growth in the wall of the uterus developing from the smooth muscle layer. These masses may cause a number of menstrual symptoms, affect fertility or remain asymptomatic and not cause any complications. Read more on what are uterine fibroids.
Types of Uterine Fibroids
There are different types of fibroids depending on its location in the uterus.
- Intramural or myometrial fibroids are situated within the muscular wall of the uterus.
- Subserosal fibroids are located on the outer surface of the uterus beneath the serosa or the peritoneum covering the outside of the uterus. Large subserosal fibroids may press upon the bladder in front or the rectum behind the uterus and give rise to urinary complications or constipation as a result.
- Submucosal fibroids are located within the uterine cavity underneath the endometrium. It likely to give rise to prolonged, heavy periods. Submucosal fibroids may occasionally be the cause of infertility and if very large, it may cause problems during pregnancy and childbirth.
- Pedunculated fibroids may be connected to the outside of the uterus by a pedicle or stalk. It may also be seen hanging within the uterine cavity by a stalk and are known as fibroid polyps or pedunculated fibroids. A pedunculated fibroid may form within the uterine cavity as a result of repeated attempts made by the uterus to remove a submucosal polyp.
Causes and Risk Factors of Uterine Fibroids
It is not known for sure what causes the development of uterine fibroids but certain factors may be involved.
- Female hormones estrogen and progesterone promote the growth of uterine fibroids. This is evident by the fact that fibroids occur in women of childbearing age, more frequently after the age of 30, and usually regress after menopause.
- Genetic factors may be involved in the development of fibroids.
- Family history – having a family member with fibroids may increase the risk of developing one.
- Obesity has been linked to increased risk of developing fibroids. Women with a high body mass index (BMI) are more likely to develop fibroids.
- Uterine infections, high blood pressure, and alterations in growth factor expression have all been suggested by researchers as risk factors.
- Potentially protective factors are pregnancy and childbirth. Nulliparous women (who have never given birth to a child) are more likely to develop fibroids.
- Early menarche is the onset of menstruation before the age of 10 years and may be an associated risk.
- Dietary factors have been suggested as possible risk factors with a focus on excessive consumption of red meat and alcohol. Eating plenty of green vegetables may have a protective action. More research is needed to prove such claims.