Understanding Uterine Fibroids (Fibroids)

What Are Uterine Fibroids?

Uterine fibroids, also called leiomyomas or simply fibroids, are common, noncancerous growths that develop from the smooth muscle of the uterus. They are among the most common gynecologic conditions affecting people during their reproductive years. Although fibroids are often referred to as “tumors,” they are almost always benign and are not considered a form of uterine cancer.

Fibroids vary considerably in size, number, and location. Some are too small to be seen without imaging, while others may grow large enough to change the shape of the uterus. A person may have a single fibroid or multiple fibroids, and symptoms can range from none at all to significant pelvic discomfort or reproductive concerns.

Many fibroids are discovered incidentally during routine pelvic examinations or imaging performed for unrelated reasons. Others come to medical attention because they cause symptoms such as heavy menstrual bleeding, pelvic pressure, painful periods, frequent urination, or difficulty becoming pregnant.

Whether a fibroid requires treatment depends on several factors, including its size, location, rate of growth, associated symptoms, reproductive goals, and overall health. Many patients with fibroids never require treatment, while others benefit from medication, minimally invasive procedures, or surgery.

Types of Uterine Fibroids

Fibroids are generally classified according to where they develop within or around the uterus. Their location is often more important than their size when determining whether they are likely to cause symptoms or affect fertility.

Intramural Fibroids

Intramural fibroids develop within the muscular wall of the uterus and are the most common type of uterine fibroid. Depending on their size, they may contribute to heavy menstrual bleeding, pelvic pressure, painful periods, or enlargement of the uterus.

Submucosal Fibroids

Submucosal fibroids grow just beneath the lining of the uterus and extend into the uterine cavity. Although they are less common than intramural fibroids, they are more likely to contribute to abnormal uterine bleeding and may interfere with embryo implantation or pregnancy. Even relatively small submucosal fibroids may affect fertility because they distort the uterine cavity.

Subserosal Fibroids

Subserosal fibroids develop along the outer surface of the uterus. These fibroids are less likely to affect menstrual bleeding or fertility but may cause pelvic pressure, abdominal fullness, constipation, or urinary symptoms if they become large enough to press on nearby organs.

Pedunculated Fibroids

Some fibroids grow on a narrow stalk, known as a peduncle. These are called pedunculated fibroids and may develop either inside or outside the uterus. In some cases, they can cause pain if the stalk twists and reduces blood flow to the fibroid.

Because different types of fibroids affect the uterus in different ways, identifying their location is an important part of fertility evaluation and treatment planning.

Common Uterine Fibroid Symptoms

Many people with uterine fibroids have no symptoms and may never realize they have them. When symptoms do occur, they often depend on the number, size, and location of the fibroids rather than simply how large they are.

Common symptoms may include:

• Heavy or prolonged menstrual bleeding
• Painful periods (dysmenorrhea)
• Pelvic pressure or pelvic pain
• A feeling of fullness or abdominal bloating
• Frequent urination
• Difficulty completely emptying the bladder
• Constipation
• Pain during intercourse
• Lower back pain
• Difficulty becoming pregnant in some patients

Symptoms often develop gradually and may worsen as fibroids grow. However, symptom severity does not always correlate with fibroid size. For example, a small submucosal fibroid may cause significant bleeding or fertility concerns, while a much larger subserosal fibroid may cause few or no symptoms.

What Causes Uterine Fibroids?

The exact cause of uterine fibroids is not fully understood. Researchers believe that fibroids develop from a single muscle cell within the uterus that begins growing abnormally. Over time, that cell divides repeatedly to form a benign growth composed of smooth muscle and connective tissue.

Several factors appear to influence fibroid development and growth, including:

• Genetics and family history
• Estrogen and progesterone exposure during the reproductive years
• Age
• Race and ethnicity
• Body weight and metabolic health

Because fibroids often respond to estrogen and progesterone, they commonly grow during the reproductive years and frequently shrink after menopause, when hormone levels naturally decline.

Although many risk factors have been identified, having one or more risk factors does not necessarily mean a person will develop fibroids, and many people with fibroids have no identifiable cause.

Uterine Fibroids & Fertility

Many people with uterine fibroids are able to conceive naturally and have healthy pregnancies. In fact, most fibroids do not cause infertility. However, depending on their size, number, and especially their location within the uterus, some fibroids may reduce the likelihood of conception or affect pregnancy outcomes.

Whether a fibroid affects fertility depends less on how large it is and more on whether it changes the shape of the uterine cavity, interferes with embryo implantation, blocks the fallopian tubes, or alters normal uterine function. Because every patient’s situation is unique, fertility specialists evaluate fibroids within the context of age, ovarian reserve, reproductive history, and other fertility factors before recommending treatment.

How Fibroids May Affect Fertility

In some patients, uterine fibroids may contribute to fertility challenges by:

• Distorting the uterine cavity and reducing available space for embryo implantation
• Altering blood flow to the uterine lining
• Changing the shape of the endometrial cavity
• Blocking one or both fallopian tubes in rare situations
• Interfering with sperm transport or embryo movement within the uterus
• Increasing uterine inflammation in certain circumstances

It is important to remember that many patients diagnosed with fibroids have no difficulty becoming pregnant. A fertility evaluation helps determine whether fibroids are likely contributing to infertility or whether another factor may better explain difficulty conceiving.

Which Fibroids Are Most Likely to Affect Fertility?

Not all fibroids influence fertility equally.

Submucosal fibroids, which grow into the uterine cavity, are the type most commonly associated with reduced fertility and lower implantation rates because they directly affect the area where an embryo implants.

Large intramural fibroids may also affect fertility when they significantly distort the uterine cavity or alter the normal structure of the uterus.

Subserosal fibroids, which grow along the outside of the uterus, generally have little or no effect on fertility because they do not usually change the shape of the uterine cavity.

For this reason, fertility specialists often recommend treatment only when a fibroid is likely to interfere with conception, embryo implantation, pregnancy, or IVF outcomes rather than simply because a fibroid is present.

How Uterine Fibroids Are Diagnosed

Many uterine fibroids are discovered during routine pelvic examinations or imaging performed for another reason. When symptoms such as heavy menstrual bleeding, pelvic pressure, or infertility are present, additional evaluation may help determine the number, size, and location of fibroids.

Diagnosis commonly begins with a review of symptoms, menstrual history, medical history, and reproductive goals. A pelvic examination may identify an enlarged or irregularly shaped uterus, although imaging is usually needed to confirm the diagnosis.

Diagnostic testing may include:

• Transvaginal ultrasound
• Saline infusion sonography (saline sonogram)
• Hysteroscopy
• Magnetic resonance imaging (MRI) in selected situations

These studies help fertility specialists determine whether fibroids are affecting the uterine cavity, identify additional uterine conditions such as polyps or congenital uterine differences, and guide treatment planning.

For patients trying to conceive, evaluation often includes a comprehensive fertility assessment in addition to imaging. Ovarian reserve testing, ovulation assessment, semen analysis, and review of reproductive history help determine whether fibroids are the primary fertility concern or one of several contributing factors.

Uterine Fibroid Treatment Options

Treatment depends on the patient’s symptoms, age, reproductive goals, the number and location of fibroids, and whether pregnancy is desired now or in the future. Not every fibroid requires treatment, and many patients are safely managed through observation alone.

Treatment options may include:

• Observation with periodic monitoring
• Medications to help manage heavy menstrual bleeding or pelvic pain
• Hormonal therapies for symptom management
• Minimally invasive surgical procedures
• Myomectomy, a surgical procedure that removes fibroids while preserving the uterus

For patients pursuing pregnancy, treatment recommendations focus not only on relieving symptoms but also on preserving or improving fertility whenever appropriate. Myomectomy may be recommended when fibroids significantly distort the uterine cavity or are believed to interfere with implantation or pregnancy.

Because every patient’s circumstances differ, fertility specialists carefully weigh the potential benefits of treatment against the risks of surgery before making individualized recommendations.

Common Questions About Uterine Fibroids

What are uterine fibroids?

Uterine fibroids are common, noncancerous growths that develop from the muscle of the uterus. Also called leiomyomas, fibroids vary in size, number, and location. Many cause no symptoms, while others may contribute to heavy menstrual bleeding, pelvic pressure, painful periods, or fertility concerns.

Are uterine fibroids cancerous?

No. The overwhelming majority of uterine fibroids are benign (noncancerous). Cancerous tumors that develop in the uterine muscle are rare and are not believed to develop from existing fibroids.

What causes uterine fibroids?

The exact cause is unknown, but genetics, reproductive hormones such as estrogen and progesterone, age, and family history are believed to contribute to fibroid development. Researchers continue to study why some people develop fibroids while others do not.

Can uterine fibroids cause infertility?

Some fibroids may affect fertility, while many do not. Fibroids that distort the uterine cavity—particularly submucosal fibroids—are more likely to interfere with embryo implantation or pregnancy than fibroids located on the outside of the uterus.

Can you get pregnant with uterine fibroids?

Yes. Many people with fibroids conceive naturally and have healthy pregnancies. Whether fibroids affect pregnancy depends on their size, number, and location, as well as other fertility factors.

Do all uterine fibroids need to be removed?

No. Many fibroids require no treatment, particularly if they are not causing symptoms or affecting fertility. Treatment recommendations are individualized based on symptoms, reproductive goals, and the characteristics of the fibroids.

How are uterine fibroids diagnosed?

Fibroids are commonly diagnosed using transvaginal ultrasound. Depending on the clinical situation, saline infusion sonography, hysteroscopy, or MRI may also be recommended to better evaluate the uterus and guide treatment planning.

What symptoms do uterine fibroids cause?

Symptoms vary widely and may include heavy menstrual bleeding, painful periods, pelvic pressure, frequent urination, constipation, abdominal fullness, pain during intercourse, or fertility challenges. Many patients have no symptoms at all.

Can fibroids cause heavy menstrual bleeding?

Yes. Heavy or prolonged menstrual bleeding is one of the most common symptoms of uterine fibroids, particularly when fibroids affect the uterine lining or distort the uterine cavity.

Can fibroids cause painful periods?

Yes. Some fibroids contribute to painful menstrual cramping or chronic pelvic discomfort. However, painful periods may also result from other conditions such as endometriosis or adenomyosis.

Can uterine fibroids affect IVF?

Some fibroids, particularly those that distort the uterine cavity, may reduce implantation rates or affect IVF outcomes. Fertility specialists evaluate whether treatment before IVF is likely to improve the chances of a successful pregnancy.

What is a myomectomy?

A myomectomy is a surgical procedure that removes uterine fibroids while preserving the uterus. It may be recommended for patients experiencing significant symptoms or when fibroids are believed to interfere with fertility or pregnancy.

Can fibroids come back after treatment?

Yes. Removing existing fibroids does not prevent new fibroids from developing in the future. The likelihood of recurrence varies based on age, genetics, and individual reproductive factors.

Do uterine fibroids shrink after menopause?

Many fibroids decrease in size after menopause because estrogen and progesterone levels naturally decline. However, not every fibroid shrinks, and persistent symptoms should still be evaluated by a healthcare provider.

When should I see a fertility specialist about uterine fibroids?

You may benefit from a fertility evaluation if you have uterine fibroids and are having difficulty becoming pregnant, have experienced recurrent pregnancy loss, are preparing for IVF, or have fibroids that significantly distort the uterine cavity. A fertility specialist can determine whether the fibroids are likely contributing to reproductive challenges and recommend an individualized treatment plan.

Learn More About Uterine Fibroids

Although uterine fibroids are common, their impact on reproductive health varies considerably from one person to another. A comprehensive evaluation can help determine whether fibroids are contributing to symptoms, infertility, or pregnancy concerns and whether treatment is appropriate.

At Spring Fertility, our board-certified reproductive endocrinologists evaluate uterine health, ovarian reserve, reproductive history, and overall fertility to develop personalized treatment recommendations that align with your family-building goals.

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