Although the exact cause is unknown, the growth of fibroids seems to be related to a gene that controls cell growth. When this gene functions normally, cells grow normally. When the gene is not functioning, cells grow and divide at an accelerated rate. Fibroid growth is affected by the reproductive hormones estrogen and progesterone. When these hormone levels decrease at menopause, many of the symptoms of fibroids begin to resolve.
RISK FACTORS FOR FIBROID
- Number of pregnancies— Women with one or more pregnancies that extended beyond 5 months have a decreased risk of fibroid formation.
- Use of birth control pills— Use of birth control pills can generally protects against fibroids, but use of the pill at an early age (between age 13 and 16) may be associated with an increased risk.
- Smoking— Women who smoke appear to have a decreased risk of having fibroids. This may be due to the estrogen lowering effect if smoking.
- Diet— Eating large amounts of red meats is associated with an increased risk, and consumption of green vegetables decreases risk. Fibroid symptoms The majority of fibroids are small and do not cause any symptoms at all
- Increased uterine bleeding: Fibroids may cause the menstrual bleeding to be heavier, or increase in the duration of bleeding or may cause bleeding in between periods. The presence and degree of uterine bleeding is determined mainly by the location of the fibroid. Women with fibroids that protrude into the uterus are more likely to have significant increases in bleeding.
- Pelvic pressure and pain: Larger fibroids may cause a sense of pressure and fullness in the abdomen, similar to that caused by pregnancy. If the fibroid is pressing on the bladder, frequent urination can occur. A fibroid that pushes on the rectum can cause constipation, and one that puts pressure on the cervix can result in painful intercourse.
- Infertility and miscarriage: A large fibroid may distort the pelvic anatomy sufficiently to make it difficult for the fallopian tube to capture an egg at the time of ovulation. Fibroids in the muscle portion of the uterus may cause an alteration or reduction of blood flow to the uterine lining making it more difficult for an implanted embryo to grow and develop. If a fibroid protrudes into the uterine cavity or causes distortion of the uterine cavity, it may present a mechanical barrier to implantation. Also it may act as a foreign body and result in an inflammatory reaction that makes the uterine environment hostile for an embryo to implant.
- Pregnancy complications: There is a slightly increased risk of certain problems during pregnancy in women with very large fibroids, including difficulties with labor, breech presentation of the fetus, premature rupture of the “bag of waters”, and abruptio placenta (a condition in which the placenta separates from the uterine wall during the pregnancy). These problems are more likely if the placenta is implanted over the area of the large fibroid. However, many women with fibroids have completely normal pregnancies and deliver healthy babies with no complications.
DIAGNOSIS OF FIBROIDS
- Larger fibroids, especially those that protrude on the outside of the uterus may be felt during a routine pelvic exam. However, in an infertility centre, most fibroids will be detected by ultrasound.
- Ultrasound (Vaginal and Abdominal) allows the detection of much smaller fibroids than cannot be appreciated by a pelvic exam. Ultrasound is also able to determine the exact number, size and location of the fibroids with respect to the uterine cavity.
- Hysterosalpingogram – The hysterosalpingogram uses clear dye that shows up on x-ray film to separate the walls of the uterine cavity.it can detect intracavitary fibroids as filling defects inside the uterine cavity. It has an additional advantage of being able to determine whether the fallopian tubes are blocked.
- Hysteroscopy – Insertion of a fiberoptic telescope through the vagina and cervix and into the uterus can detect fibroids that are within the uterine cavity or causing significant distortion of the cavity and at the same sitting they can be resected by using a resectoscope
- MRI – Magnetic resonance imaging uses high powered magnets to determine the difference between different types of tissue. It is very good for determining the difference between fibroid tissue and normal uterine tissue. It is also helpful for distinguishing the difference between fibroids and another less common problem of the uterus known as adenomyosis.
- Surgery – Occasionally fibroids are identified during an abdominal surgery such as a laparoscopy . This is useful for fibroids that cause distortion of the outer contour of the uterus or those that are only attached to the uterus by a thin stalk.
TREATMENT OF FIBROIDS
- If there are no symptoms, treatment is usually not required. In women with significant symptoms, treatment may be medical or surgical.
- Medical treatment – Medications called gonadotropin-releasing hormone (GnRH) analogs are commonly used in the medical treatment of fibroids. They are usually only given as a temporary measure, such as during the time a woman is preparing for surgery to remove the fibroids. GnRH analogs cause a reduction in estrogen levels. Most women taking these medicines have a cessation of the menstrual period. The lack of periods can help women with anemia from fibroid related heavy or prolonged menstrual bleeding to build their blood counts up before surgery. In some cases, GnRH analogs can cause shrinkage of fibroids which may allow them to be removed through a smaller incision. OC pills may be used again as a temporary measure.
- Surgical treatment – The type of surgery needed is dependent upon the size, number and location of fibroids. In addition, the underlying problem is important. Obviously, a woman with infertility who wants to keep her uterus would be treated differently than a peri-menopausal woman who is done with her childbearing. Procedures that are performed for women to maintain the capability for childbearing or to improve fertility include:
- Abdominal myomectomy — Myomectomy means removal of a fibroid. In an abdominal myomectomy, an incision is made through the abdomen to expose the uterus, and the fibroids are excised from the uterine muscle. This approach is most appropriate in women who want to maintain childbearing, and who have multiple fibroids or very large fibroids.
- Laparoscopic myomectomy —A fiberoptic telescope inserted through a tiny incision in or below the belly button, through which the surgeon can visualize the uterus. Additional tiny incisions are used to introduce long thin operating instruments which can be manipulated to remove the fibroids and repair the uterus afterward. Laparoscopy is most appropriate for women with one or two small to moderate sized fibroids that are located on the outer surface of the uterus.
- Hysteroscopic myomectomy — This involves placing a fiberoptic telescope through the vagina and cervix and into the uterine cavity. Long thin surgical instruments can be introduced into the uterus using an operative channel in the hysteroscope. Saline is used to keep the walls of the uterus separated. This procedure can only be done on fibroids that mostly located within the uterine cavity.
- Uterine artery embolization – Uterine artery embolization (UAE or UFE) is performed by a radiologist. Using x-ray, a catheter is threaded through blood vessels toward the uterus. Tiny spheres are injected into the blood vessels that feed a fibroid causing the blood supply to be blocked. Without a blood supply, the fibroid will begin to breakdown. This technique is relatively new. There is very little data on the potential risks it may cause for a woman who subsequently becomes pregnant. Recently, a multicenter Dutch study looked at the effect of uterine artery embolization on ovarian function. Doctors in the study measured a hormone (anti-mullerian hormone or AMH) which is correlated with ovarian reserve. Women who had UAE had a much more rapid decline in AMH than would have been expected. This suggests that uterine artery embolization may cause damage to the ovaries and deplete the number of eggs remaining in the ovaries. Therefore, this procedure should not be recommended for women who want to maintain childbearing potential.
- Serious complications are uncommon but can include bleeding, infection, damage to other body structures, anesthesia problems or even death. Some fear that if damage to the uterus is extensive that a hysterectomy might be required. This would be a very rare complication. About 11 to 26 percent of women who have had myomectomy will require a second surgery. In addition, abdominal and laparoscopic myomectomy carry varying degrees of risk for uterine rupture during pregnancy or labor. Due to this risk, the surgeon may recommend a cesarean section for delivery.
CONTROVERSY BETWEEN FIBROIDS AND INFERTILITY
- There is much disagreement amongst physicians about when a myomectomy for infertility should be performed. Most would agree that fibroids that are within the uterine cavity or causing significant distortion of the cavity should be removed. However, what about a single small fibroid that is located within the muscular wall of the uterus but does not protrude into or distort the cavity? What if there were two such fibroids? What about a very large fibroid that is only attached to the uterus by a thin stalk. Much of the data that is published in the medical literature compares the number of pregnancies in a group of patients before and after a procedure. However, this doesn’t prove that a myomectomy was responsible for an improvement in fertility just because the pregnancy occurred after the surgery. The best type of study looks at a larger group of women with identical fibroids. One half of the group would have a myomectomy and the other group would have a “sham” surgery where no fibroid was removed. Obviously, this type of study could never be done so the controversy is likely to continue for some time.