The uterine fibroids are (non-cancerous) tumors that arise from the muscular layer (myometrium) of the uterus. The uterus is made primarily of smooth muscle cells, designed to expand with pregnancy and to assist with vaginal delivery with contractions at the end of pregnancy. Uterine fibroids can grow under the endometrium (submucosal), in the myometrium (intramural) or under the outer (serous) lining of the uterus (subserosal).
Uterine fibroids: causes
Uterine fibroids are very common and are found in about 25% of women between the ages of 18 and 45. African American women are at an increased risk of developing uterine fibroids compared to white women. Other risk factors for the development of uterine fibroids include abortion, drinking alcohol, and genetic factors. It is also believed that high consumption of red meat and ham could increase the risk of fibroids, while consumption of fruits and vegetables would decrease it. However, this has not been conclusively proven. The use of birth control pills seems to reduce the risk of developing uterine fibroids.
It is not yet well understood why uterine fibroids develop. There are some genetic abnormalities in smooth muscle cells that increase the risk of them. On the other hand, fibroids appear to be under hormonal control, although the precise mechanism is not fully understood either.
Uterine fibroids: symptoms and consequences
Uterine fibroids can cause abnormal uterine bleeding, pelvic pressure and have a negative effect on fertility. In general, fibroids that press the endometrium can cause abnormal bleeding. This includes submucosal fibroids and large intramural fibroids. When the fibroids grow too much, the uterus expands and presses on nearby organs, such as the urinary bladder and rectum. This can lead to a feeling of fullness, constipation and frequent urination.
In extreme cases the uterus can reach the size of a baby at term, reaching the liver and the diaphragm. Fibroids usually do not cause extreme pain, however, sometimes a fibroid can lose its blood supply due to rapid growth. This causes the fibroid to die, something that can be very painful. Usually, the pain will improve in a few days but sometimes requires a surgical intervention.
Fibroids that press on the endometrium may decrease the chances of becoming pregnant, as it would interfere with the implantation of the embryo. Unfortunately, there are no scientific studies evaluating the effects of fibroids on fertility.
Larger fibroids can be identified during a physical examination. If not, ultrasounds can identify most of the fibroids.