Uterine fibroids are growths in the uterus. They are not cancer. Fibroids can grow on the inside of the uterus, within the muscle wall of the uterus, or on the outer surface of the uterus. They can change the shape of the uterus as they grow. This can make it hard for you to get pregnant, or it can cause problems during a pregnancy.

Over time, the size, shape, location, and symptoms of fibroids may change.

Your risk for uterine fibroids increases as you age, especially from your 30s and 40s through menopause. Most have mild or no symptoms. But fibroids can cause bad pain, bleeding, and other problems.

The cause of fibroids is not known. But the hormones estrogen and progesterone can make them grow. Your body makes the highest levels of these hormones during the years you have periods. After menopause, when hormone levels decrease, fibroids often shrink or disappear.

Uterine fibroids usually need treatment when they cause:

• Anemia from heavy fibroid bleeding.
• Ongoing low back pain or a feeling of pressure in the lower belly.
• Trouble getting pregnant.
• Problems during a past pregnancy, such as miscarriage or preterm labor.
• Problems with the urinary tract or bowels.

Depending on the reasons you need treatment, one type of treatment may work better for you than another.

Uterine fibroid embolization is a procedure that blocks blood flow to fibroids in the uterus. It's not surgery. Fibroids treated with this procedure shrink.

The doctor (a radiologist) puts a thin, flexible tube called a catheter into a blood vessel in your upper thigh (femoral artery). Then the doctor injects a substance called contrast material into the catheter. The doctor uses an X-ray on a video screen to see the arteries and guide the catheter to the arteries that supply blood to the fibroid. Small particles are injected into those uterine arteries through the catheter. These particles build up in the arteries and block blood flow to the fibroid. The rest of the uterus usually isn't harmed, because it's supplied by other arteries.

Uterine fibroid embolization can be used to control heavy, long-lasting menstrual bleeding when:

• You have tried hormones, but they didn't relieve your symptoms.
• You don't plan to get pregnant. It may not be recommended for people who have plans to get pregnant. The procedure has an unknown effect on fertility. And there may be a higher risk for pregnancy problems after.
• You don't want to have surgery (myomectomy or hysterectomy). You would need only local anesthesia for this procedure. And the doctor doesn't have to make any cuts in your skin. For most people, this means no hospital stay and a quicker return to normal activities, compared to surgery.
• You have other health problems, such as severe lung or liver disease, that make it risky for you to have surgery or use hormones.

Embolization usually works well to treat fibroids. It reduces the size of fibroids. And in most cases, treatment improves symptoms. But fibroids can come back. Some people need more treatment several years after they have embolization.

The chance of a problem after embolization is low. But the risks include:

• Post-embolization syndrome. This is a set of symptoms that can last for a couple of weeks after the procedure. It can include pain, fever, and nausea.
• Problems with the ovaries or early menopause. And it may increase risk for certain pregnancy problems.
• Infection.
• Unplanned hysterectomy. In rare cases, a hysterectomy is needed to treat an infected or damaged uterus.
• Pulmonary embolism.

Although some people can get pregnant after this procedure, experts don't yet fully know the risks to pregnancy.

If you're thinking of having this procedure, look for a radiologist who has done it many times with few problems.

Your doctor might recommend this procedure if:

• You've tried hormones, and they didn't work for you.
• You have another health problem that makes surgery or hormones too risky.
• You don't plan to get pregnant.