Uterine fibroids are very common non-cancerous (benign) growths that develop in the muscular wall of the uterus. They can range in size from very tiny (a quarter of an inch) to larger than a cantaloupe. Occasionally, they can cause the uterus to grow to the size of a five-month pregnancy. In most cases, there is more than one fibroid in the uterus. While fibroids do not always cause symptoms, their size and location can lead to problems for some women, including pain and heavy bleeding.
Fibroids can dramatically increase in size during pregnancy. This is thought to occur because of the increase in estrogen levels during pregnancy. After pregnancy, the fibroids usually shrink back to their pre-pregnancy size. They typically improve after menopause when the level of estrogen, the female hormone that circulates in the blood, decreases dramatically. However, menopausal women who are taking supplemental estrogen (hormone replacement therapy) may not experience relief of symptoms.
Uterine fibroids are the most common tumors of the female genital tract. You might hear them referred to as “fibroids” or by several other names, including leiomyoma, leiomyomata, myoma and fibromyoma. Fibroid tumors of the uterus are very common, but for most women, they either do not cause symptoms or cause only minor symptoms.
These develop under the outside covering of the uterus and expand outward through the wall, giving the uterus a knobby appearance. They typically do not affect a woman’s menstrual flow, but can cause pelvic pain, back pain and generalized pressure. The subserosal fibroid can develop a stalk or stem-like base, making it difficult to distinguish from an ovarian mass. These are called pedunculated. The correct diagnosis can be made with either an ultrasound or magnetic resonance (MR) exam.
These develop within the lining of the uterus and expand inward, increasing the size of the uterus, and making it feel larger than normal in a gynecologic internal exam. These are the most common fibroids. Intramural fibroids can result in heavier menstrual bleeding and pelvic pain, back pain or the generalized pressure that many women experience.
These are just under the lining of the uterus. These are the least common fibroids, but they tend to cause the most problems. Even a very small submucosal fibroid can cause heavy bleeding – gushing, very heavy and prolonged periods.
Prevalence of Uterine Fibroids
Twenty to 40 percent of women age 35 and older have uterine fibroids of a significant size. African American women are at a higher risk for fibroids: as many as 50 percent have fibroids of a significant size. Uterine fibroids are the most frequent indication for hysterectomy in premenopausal women and, therefore, are a major public health issue. Of the 600,000 hysterectomies performed annually in the United States, one-third are due to fibroids
Uterine Fibroid Symptoms
Most fibroids don’t cause symptoms—only 10 to 20 percent of women who have fibroids require treatment. Depending on size, location and number of fibroids, they may cause:
- • Heavy, prolonged menstrual periods and unusual monthly bleeding, sometimes with clots; this can lead to anemia
- • Pelvic pain and pressure
- • Pain in the back and legs
- • Pain during sexual intercourse
- • Bladder pressure leading to a frequent urge to urinate
- • Pressure on the bowel, leading to constipation and bloating
- • Abnormally enlarged abdomen
Will it work for me?
The answer to this question depends entirely on your individual situation. If uterine fibroid embolization (UFE) is to be effective, several things must be true:
First, your symptoms have to be caused by a fibroid. This may seem like an obvious point, but not every woman with bleeding or pain has fibroids, and not every fibroid causes symptoms. Second, your symptoms should be significant enough that they are impacting your quality of life. Although UFE is minimally invasive, it is still a medical procedure with potential complications. It should not be performed unless there is a real problem to fix. Third, there should be no other medical condition that makes hysterectomy a more appropriate option. For instance, if you also have a known or suspected malignancy in your cervix, ovaries, or uterus, then UFE is not appropriate as a stand-alone treatment (although it might be performed before surgery to reduce bleeding).
To be sure that each of these issues is addressed, every woman considering UFE must be completely evaluated by a doctor with experience and training in women’s health. For a list of Christie Clinic gynecologists, please click here.
Does the size, number, or location of my fibroids matter?
The embolization procedure treats all of a woman’s fibroids at once, no matter how large or where they are located.
Although UFE treats large fibroids as easily and effectively as small ones, the final size is directly comparable to the beginning size. That means that a huge fibroid will probably still be very big after embolization. Most fibroids shrink by 50-65%, or about half. That amount is enough to relieve symptoms in most women, but not in all.
Some fibroids get a portion of their blood supply from vessels other than the uterine artery. This is called “parasitized flow,” and is impossible to detect. The source can be ovarian arteries, intestinal arteries, and arteries from other structures in the pelvis. We are often unable to find these vessels, and may not be able to treat them safely even if they can be found. If a lot of “parasitized flow” is present (and there is no way to predict this), then the fibroid might not shrink after UFE.
What happens to the fibroid(s)?
The embolized fibroid immediately loses its supply of oxygen, nutrients, and hormonal stimulation. Over the subsequent weeks and months, individual muscle cells in the fibroid die off and are replaced by scar tissue. The trade-off is that fibroid symptoms do not immediately disappear, as they would with hysterectomy or myomectomy.
Eventually, the fibroid is replaced by a lump of scar tissue. Because scar tissue does not respond to hormonal stimulation as fibroids do, the normal menstrual cycle no longer causes growth.
What happens to the uterus?
The uterus tolerates the UFE procedure very well. Injury to the normal uterus is extremely rare. There are two main theories to explain these findings. First, the arterial branches that go to normal uterine tissues are tiny, while the arteries that go to the fibroid are very large. Injected polyvinyl alcohol (PVA) particles are too big to enter vessels leading to the normal uterus, so they roll right past these vessels and go where the blood flow and vessel diameter are greatest. The fibroids, by being so greedy for blood flow, preferentially absorb the blood-borne PVA. Second, the uterus is able to “recruit” blood supply from adjacent organs, primarily the cervix, vagina, and pelvic floor.
What happens to the particles?
The most common material used for UFE is polyvinyl alcohol (PVA). All PVA is approved for human use by the FDA, and some specifically for UFE. PVA is a plastic powder, and a permanent embolic agent. The particles do not get absorbed, do not dissolve, and cannot migrate to other parts of the body once they are in place. PVA causes little or no reaction by the body, and has never been associated with the kind of delayed complications that have been seen with breast implants.
Acryilic spheres are an unique embolic agent FDA approved for UFE. These spheres are very uniform in size, and slightly compressible. They are permanent embolic agents, with similar properties as PVA.
Do the fibroids come back?
The UFE shrinks, but does not remove, the fibroids. Since they don’t actually “go away”, the question actually has three parts: a) can the shrunken fibroids regrow, b) can new fibroids develop after UFE, and c) if fibroids regrow or new ones form, can they cause enough symptoms to require treatment? In several large randomized prospective studies comparing UFE to surgical treatments, approximately 10% of the UFE patients needed a second treatment of some sort. Some of these treatments were related to incomplete shrinkage of the fibroids. Patients who have many years of menstrual cycles after UFE can develop new fibroids, some of which can cause symptoms. This is not too surprising, as all of a woman’s reproductive organs are intact after UFE compared to hysterectomy. Fortunately, these problems are rare, but can often be managed with repeat UFE.
Will I still have menstrual periods?
95% of women will continue to have menstrual periods after UFE. Roughly 5% of women in one published study did enter menopause after UFE, but the reason for this is not clear. It may be coincidental, but there is also the possibility that some of the injected particles caused a reduction of blood flow to the ovaries.
Will I still be able to have children?
As noted above, a small number of women enter menopause after UFE. The rest maintain their baseline fertility. We know this because several women have had successful pregnancies, carried to term, after UFE. We also know from years of experience that, when the uterine artery is embolized or surgically tied off for pelvic trauma, fertility remains normal. What we do not know is whether UFE will shrink fibroids enough to improve fertility in women who have had problems with miscarriage
Does it hurt?
The amount of pain that women experience during and after UFE is extremely variable. We do not yet have a good mechanism for predicting the degree of pain that an individual patient will feel, but it does not seem to be related to fibroid size or number. Most women experience at least moderate cramping. Some women have more pain. Fortunately, the pain can be controlled with medications, and it usually only lasts for 24-72 hours. Some women prefer to remain in the hospital overnight, but are home the next day by noon.
Is it dangerous?
When performed by an experienced physician, embolization is a very safe procedure. Although there can be complications, they are uncommon.
The most serious potential complication is infection. If an infection developed after UFE, it could require hysterectomy. Of course, infections can also develop after myomectomy, hysteroscopy, or hysterectomy. Patients should be treated with antibiotics during UFE or surgery, and pre-existing pelvic infections need to be resolved prior to the procedure.
Although unlikely, it is possible for blood flow to other organs to be blocked during UFE. This complication can result in injuries to the urinary bladder, the intestine, the ovary, or other adjacent structures. Fortunately, this complication can be avoided with careful technique and x-
ray guidance during embolization. As with infections, injury to adjacent organs is a risk of both UFE and the common surgical alternatives. The use of x-ray guidance is mandatory for UFE. The specific amount of radiation received by the uterus and ovaries in any given UFE procedure is directly related to the time required and the techniques used by the IR. While no particular dose of radiation can be shown to cause a specific risk of injury, less is better than more. Surgical and medical treatment alternatives do not use x-rays.
What do I do next?
The process of evaluating a patient for UFE begins with your women’s health care provider. He or she will verify whether you have a fibroid, and whether it is responsible for your symptoms. He or she may order special imaging studies or blood tests to be sure that there are no other problems that also need to be addressed. Your women’s health care provider along with one of our physicians can help to determine whether UFE is right for you.