Uterine fibroids, also called leiomyomas, fibromyomas, or myomas, are the commonest non-cancerous tumors in women of childbearing age. Uterine fibroids grow from the smooth muscle tissue of the uterus and may vary in size from tiny seedlings to massive lumps that can distort and expand the uterus. They may be single or multiple, very often producing no symptoms at all, and are almost never associated with increased risk of developing cancer.
Types of Uterine Fibroids
Depending on their location in the uterus, fibroids may be :
- Myometrial – located within the muscle of the uterus.
- Submucosal – just beneath the surface of the uterine lining. Submucosal leiomyomas may cause prolonged, heavy menstrual periods, and may become the one of the possible causes of infertility.
- Subserosal – just within the outer covering of the uterus. If large, these may press on the bladder or rectum and cause urinary problems or constipation.
- Pedunculated – connected by a stalk to the outer surface of the uterus or hanging within the uterine cavity.
Causes of Uterine Fibroids
There is no definite known cause of a leiomyoma in the uterus but certain factors may influence their development.
- Uterine fibroids are common pelvic tumors that develop in women of childbearing age, more common in women over the age of 30, usually regressing after menopause.
- It is more common in African-American women than in Caucasians and fibroids also tend to occur at an earlier age and reach larger proportions in the former group.
- Genetic factors seem to play a part in the development of uterine fibroids
- The female hormone, estrogen, seems to enhance growth of fibroids.
Symptoms of Uterine Fibroids
In a large number of cases, uterine fibroids do not produce any symptoms, often being detected only incidentally during a routine pelvic examination or when fertility tests are conducted in cases of infertility. Symptoms, if present, may include :
- Menorrhagia or heavy menstrual bleeding, which may lead to anemia.
- Prolonged periods.
- Spotting or bleeding between periods.
- Dysmenorrhea or painful menstruation.
- Irregular periods.
- Heaviness or pelvic discomfort, sometimes also described as bearing down ache.
- Recurrent spontaneous abortion.
- Frequency of urination.
- Back pain.
- Edema or swelling of the leg.
- A degenerating fibroid can cause acute pain.
- Twisting or torsion of a pedunculated fibroid can cause severe lower abdominal pain.
- Abdominal lump – large fibroids may be felt abdominally.
Relationship of Fibroids with Infertility and Pregnancy
Fibroids normally do not interfere with conception or pregnancy, but in rare cases they may block the fallopian tubes or prevent sperm from entering the fallopian tubes. A submucosal fibroid may even prevent implantation of the embryo on the uterus wall.
Large submucosal fibroids or multiple fibroids may sometimes cause problems during pregnancy, such as :
- Abdominal pain
- Risk of miscarriage
- Premature labor and delivery
- Placental separation and bleeding
- Abnormal fetal position in the uterus.
- Increased chances of a cesarean section.
As a rule, however, fibroids do not cause any problem during pregnancy and no treatment is necessary. They may increase in size during pregnancy, but usually return to their original size after delivery. Fibroids are not routinely removed during a cesarean section as there is increased risk of bleeding.