Uterine fibroids at a glance
- Uterine fibroids are noncancerous tumors of smooth muscle tissue that form in the uterus and can affect fertility in several ways, requiring treatment.
- Uterine fibroids can alter the structure and size of the uterus, the cervix and the fallopian tubes, interfering with fertilization, embryo implantation and successful birth.
- The National Institutes of Health (NIH) estimates that 5-10 percent of infertile women have uterine fibroids and further suggests that uterine fibroids may be the sole cause in up to 2.4 percent of infertility cases.
- Symptoms include infertility, pressure, bloating, strong pain and bleeding.
- Treatments for uterine fibroids vary according to specifics of the individual case and include hormone therapy and surgery to remove the fibroids or the uterus.
What are uterine fibroids?
Fibroids are benign (noncancerous) tumors that develop from smooth muscle cells and they can occur in various parts of the body. When they occur in the uterus they can disrupt a woman’s fertility. Also called myomas or leiomyomas, uterine fibroids are fairly common and so is their relationship to infertility.
According to the American Society for Reproductive Medicine (ASRM) about 20 percent of reproductive age women have uterine fibroids. The presence of uterine fibroids also affects the success of assisted reproductive technologies, such as in vitro fertilization (IVF).
Scientists aren’t sure what causes uterine fibroids, but think that they form from a stem cell in the uterus’ smooth muscle tissue that divides repeatedly until it creates a rubbery mass. Researchers suspect that genetic changes have a role in creating uterine fibroids. Fibroids also respond to hormones (estrogen is known to increase their growth), and these may also play a role in their formation.
The primary risk factors for getting uterine fibroids are:
- Heredity, with higher risk for women whose mother or sister has had them
- Race, because African-American women are more likely than any other race to get them, and to have more of them, of larger size and at a younger age
- Other factors, such as starting menstruation early, being obese, drinking alcohol, using birth control, vitamin D deficiency, and a diet high in red meat and low in vegetables, fruit and dairy.
Uterine fibroids are generally classified into three types related to their location.
- Subserosal fibroids are located in the outer wall of the uterus, comprise about 55 percent of uterine fibroids, and do not appear to affect fertility
- Intramural fibroids occur in the muscular layers of the uterus’ wall, account for about 40 percent of uterine fibroids, and have a small effect on fertility
- Submucosal fibroids, which make up only 5 percent of uterine fibroids, protrude into the uterine cavity and appear to have the greatest effect on fertility, hampering embryo implantation and carrying a pregnancy to live birth.
How uterine fibroids affect fertility
Most women with uterine fibroids do not suffer any negative effects on their fertility. When fibroids do affect fertility, it can be in the following ways:
- Fibroids can change the shape of the uterus and/or the cervix, affecting the movement of sperm for fertilization or the fertilized embryo’s ability to move to the uterus
- Fibroids can block fallopian tubes, also inhibiting necessary sperm and embryo movement
- Larger fibroids (>5 cm) can lower rates of pregnancy, and those that push into the uterine cavity can decrease the chance of pregnancy
- The presence of hormones also is thought to decrease prospects for successful embryo implantation and carrying a pregnancy to term, due to changes in the endometrium (uterus lining).
Symptoms and diagnosis of uterine fibroids
In many instances, women with uterine fibroids never experience any symptoms. Sometimes an inability to get pregnant causes a woman to seek a fertility exam, and the fibroids are discovered in that manner.
When symptoms do present, the size and location of the fibroids can influence their severity. These include:
- Menstrual periods that go on for more than a week
- Heavy bleeding during the period
- Pain or pressure in the pelvic region
- Need to urinate frequently and/or difficulty emptying the bladder.
These symptoms, without any other suspected cause, may be reason to seek medical evaluation. Women experiencing the sudden onset of strong pelvic pain or extraordinary vaginal bleeding should see a doctor immediately.
Uterine fibroid diagnosis often occurs during a pelvic exam when the physician feels an abnormal shape to the uterus. Lab tests may be used to evaluate if the woman has anemia due to loss of blood caused by the fibroid or to eliminate the prospect of thyroid conditions and blood disorders.
Imaging tests and procedures are the primary method of diagnosing uterine fibroids. These include:
- Ultrasound to show size, type and location
- MRI to show size, type and location
- Hysteroscopy, using a hysteroscope inserted into the uterus through the cervix, giving the physician a view of the uterine cavity and the opening into the fallopian tubes
- Hysterosonography, which involves a saline solution to expand the uterus and a sonogram to provide images
- Hysterosalpingography, often used when infertility is suspected, involves a dye and X-rays to show the condition of the uterus and fallopian tubes.
Uterine fibroid treatments
Hormones and other medications, noninvasive procedures and surgical interventions are primary treatments for uterine fibroids. Hormones and medications can reduce the size of fibroids and their symptoms but cannot cure them.
A physician might prescribe birth control pills or an intrauterine device that releases the hormone progestin. Gonadotropin-releasing hormone (Gn-RH) agonists may be given to reduce the size of fibroids prior to surgery to remove them, as well as to block production of other hormones to shrink fibroids. Other medications may be given to reduce symptoms.
Nonsurgical intervention can be done via focused ultrasound surgery, in which the woman is scanned by an MRI that reveals the location of the uterine fibroids. The physician then uses an ultrasound transducer to destroy the fibroids with sound waves. Some women may be candidates for uterine artery embolization, a minimally invasive procedure that cuts off the fibroid’s blood supply.
Fibroid removal by surgery that leaves the uterus in place is called myomectomy. This is most often used in an effort to restore fertility. Pregnancy rates following myomectomy are as high as 60 percent, according to the NIH.
Laparoscopic myomectomy is the preferred treatment. This involves smaller incisions, an internal video monitor view provided to the surgeon, and special instruments. Abdominal myomectomy is a traditional open surgery, and this may be necessary for some cases. Robotic myomectomy is similar to laparoscopic myomectomy and utilizes robotic devices.
Hysteroscopic myomectomy is often the best surgery for submucosal uterine fibroids, which cause most cases of infertility. A hysteroscope is a thin tube with a camera and special operating instruments inserted through the vagina and into the uterus. The surgeon locates the fibroids and removes them.
A hysterectomy, removal of the uterus, may be required. Following this the woman is infertile.
Risks of myomectomy include blood loss, reaction to anesthesia, infection, damage to tissue and organs, a longer hospital stay and pain. Adhesions following the surgery may have a negative effect on fertility.