Uterine Fibroids: Common, Usually Harmless Growths — Risks, Symptoms and Treatment

What they are

Uterine fibroids are the most common noncancerous (benign) tumors in women of childbearing age. You can have them and not know it, because they often cause no symptoms.

• What they're made of: muscle cells and other tissue growing in and around the wall of the uterus, or womb.
• Number and size: they vary, growing singly or in clusters — sometimes very small, and in extreme cases large enough to make it look like a pregnancy.
• Pregnancy: many women with fibroids get pregnant without problems, but some fibroids can cause infertility, pregnancy loss, or problems with fetal development or delivery.

Who is more likely to get them

Anyone female and of childbearing age can develop fibroids. Risk factors include:

• Age: older women are at higher risk.
• Race and ethnicity: Black women often get fibroids younger, and are more likely to have larger fibroids with worse symptoms.
• Family history: a mother or sister who had them.
• Other factors: periods that started before age 10, or never having been pregnant.
• Some medical conditions: obesity or vitamin D deficiency.

Risk goes down with each pregnancy, and with long-term use of birth control pills or shots.

Causes

No one knows what causes fibroids. Genetics and growth hormones may play a part, and the hormones estrogen and progesterone — which thicken the lining of the uterus each menstrual cycle to prepare for pregnancy — seem to help them grow.

Symptoms

Many women have none. When there are symptoms, they depend on the fibroids' location, size and number:

• heavy or painful periods, or bleeding between periods;
• a feeling of fullness in the lower abdomen;
• urinating often;
• pain during sex;
• lower back pain;
• trouble getting pregnant, repeated miscarriages, or early labor.

Diagnosis

Unless you have symptoms, you may not know you have fibroids. A health care provider may find them during a pelvic exam or with imaging tests.

Treatment

With no symptoms, you may not need treatment. Otherwise it depends on:

• your symptoms;
• your age — fibroids sometimes shrink during and after menopause, as hormone levels drop;
• the fibroids' location, type and size;
• whether you're pregnant or want to be.

Options include medicines that slow or stop fibroid growth, and surgery such as a hysterectomy (removal of the uterus), which may be considered if you are near or past menopause, or if the fibroids are very large or cause heavy bleeding. If you're having trouble getting pregnant, your provider may discuss infertility treatment, and may suggest an emotional support group for chronic symptoms or difficulty getting or staying pregnant.

Sources

Based on "Uterine Fibroids," MedlinePlus, National Library of Medicine, drawing on the National Institute of Child Health and Human Development; a work of the United States government in the public domain.