What is a uterine fibroid, causes, symptoms and treatment 2026

Uterine fibroids, also known medically by the names uterine fibroid tumors, leiomyomas, or simply fibroids, tend to be fairly common growths, affecting between 20 and 80 percent of women, and are usually benign (that is, not cancerous).

Sometimes they can cause symptoms ranging from mild pelvic and/or abdominal discomfort to irregular bleeding, pain, and pregnancy-related problems. Although in most cases the most common thing is that they tend to be asymptomatic.

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Although they can appear at any age, especially during a woman's reproductive stage, it is estimated that between 20 to 50 percent of women usually develop them by age 50. What's more, it is estimated that approximately 80 percent of women usually have them before the age of 50.

What are uterine fibroids?

A uterine fibroma consists of an excessive growth of smooth muscle tissue. The uterine lining, which is known as the endometrium, has a muscle so that the uterus is able to stretch during pregnancy, and finally contract during childbirth.

Types of uterine fibroids

There are different types of uterine fibroids and they can vary in size. In fact, the type of fibroid a woman develops depends directly on its location in the uterus. Below we tell you which are the most common:

• Subserosal fibroids. These are fibroids that grow on the outside of the uterus, and usually do not tend to cause symptoms unless they grow large enough to interfere with other nearby organs. In fact, they can grow so much that they can end up distorting the outer layer of the uterus, making the uterus appear larger on one side.
• Submucosal fibroids. These are fibroids that develop just beneath the uterine lining, and can extend into the uterus, probably causing menstrual problems.
• Intramural fibroids. They are those fibroids that are found inside the uterine wall, and can enlarge the uterus.
• Transmural fibromas. These are fibromas with similar characteristics to intramural fibromas, with the difference that they extend throughout the uterine wall, and can alter the shape of the uterus.
• Pedunculated fibromas. They are fibromas of subserous origin, which end up developing a stalk; that is, a thin base that supports the tumor. They can extend far from the uterus, becoming enlarged and twisted, causing severe pain.

What are the causes of uterine fibroids?

There are some known risk factors that can increase the chances of developing a uterine fibroid. However, the reality is that these tumors are quite common, and can develop even without any risk factors. What's more, even if you have a risk factor, it is possible that none will develop.

The most common risk factors include:

• Genetic factors, such as a family history of fibroids.
• Personal history of fibroids.
• Advanced age.
• Obesity.

On the other hand, although the exact cause of their formation/appearance is not known, it is suspected that hormones such as estrogen may be a common cause, given that they are estrogen-dependent tumors, and they develop - and grow - in response to this hormone.

For this reason, they usually arise during a woman's reproductive stage, when estrogen levels tend to be higher. The same thing happens, for example, during pregnancy, when fibroids can often grow extremely quickly as a result of the presence of extra estrogen in the body.

However, during menopause it is common for fibroids to decrease in size, due to the strong decrease in the production of estrogen, which ends up confirming that this hormone has a strong relationship with their appearance/decrease.

How are uterine fibroids treated?

Uterine fibroids can be treated in two ways: medically, for example through the prescription of certain medications, or surgically.

For example, if the fibroid causes discomfort and cramps, the doctor may prescribe a helpful drug to reduce pain, such as ibuprofen or acetaminophen. It is also known that GnRH (Gonadotropin-releasing hormone) helps them reduce their size, being useful before surgery.

In relation to surgical treatments, these fundamentally include three: hysterectomy, myomectomy and embolization, and they are usually especially indicated when the fibroid is too large and causes very bothersome symptoms, or interferes with nearby organs.