Endometriosis vs. Fibroids

Can fibroids be mistaken for endometriosis?

Uterine fibroids (leiomyomas) and endometriosis are chronic gynecologic conditions that affect the uterus. Fibroids are noncancerous (benign) tumors that originate in the uterine wall. Endometriosis occurs when endometrial-like tissue (tissue similar to that of the uterus) grows outside the uterus, where it doesn't belong.

Endometriosis and fibroids are not the same conditions. However, it's possible to have both at the same time. Based on symptoms alone, these conditions are sometimes confused with each other. However, diagnostic testing can be used to differentiate between the two.

This article will discuss how endometriosis and fibroids form, their symptoms, diagnostic testing, and treatment for each condition.

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How They Form: Endometriosis vs. Fibroids

It's not clear what causes or triggers endometriosis or fibroids. It is thought that family history and genetics play a role in the emergence of both conditions.

Hormonal imbalances or fluctuations in estrogen and progesterone may also impact symptom severity and disease progression.

How Endometriosis Forms

The cause of endometriosis is unknown, but there are theories regarding how it develops. One is that endometriosis originates from retrograde menstruation. This refers to the backward flow of menstrual blood into the pelvis instead of through the vagina.

Endometriosis may begin as early as adolescence or the teenage years. Endometrial lesions may even form as early as your first menstrual period. Endometrial-like lesions and scar tissue can continue to form over time, impacting the entire reproductive tract, including the ovaries and fallopian tubes.

How Fibroids Form

Uterine fibroids are tumors that originate from smooth muscle cells. These tumors are usually noncancerous.

Fibroids may affect up to 70% to 80% of people with a uterus. Fibroids are often diagnosed when a person is in their 30s or 40s, up until menopause.

Fibroids can get larger or smaller over time. Their growth often corresponds to escalations of estrogen and progesterone levels. Fibroids range from the size of a pea to the size of a grapefruit. Occasionally, they may become much larger.

You can have multiple fibroids of varying sizes simultaneously. In some instances, fibroids may grow on a stalk called a peduncle.

The three types of uterine fibroids include:

Increased Risk of Fibroids in Black Women

Fibroids are 2 to 3 times more common in Black women than women of other ethnic groups. Black women also tend to get fibroids at a younger age than White women do. (Note that when research or health authorities are cited, the terms for sex or gender from the source are used.)

The reasons for this discrepancy are not completely understood. It is thought that genetics may play a role. Lifetime stress levels, vitamin D deficiencies, and environmental factors may also be underlying causes.

Endometriosis vs. Fibroids Symptoms

Since they both affect the reproductive tract, fibroids and endometriosis may cause some of the same symptoms. Symptom severity for both disorders may range from asymptomatic (no symptoms) to severe.

Shared Symptoms

Endometriosis and fibroids may both present with the following symptoms:

  • Pain during menstruation
  • Pain during penetrative sex
  • Lower back pain
  • Infertility (more common with endometriosis than with fibroids)

Distinct Symptoms

The symptoms caused by both conditions can vary among people. You'll need to get a medical diagnosis to know which condition you have, even if you present with specific or distinct symptoms of one disease.

Symptoms of endometriosis include:

  • Very severe menstrual cramps
  • Pain during bladder or bowel movements
  • Chronic pelvic pain
  • Deep vaginal pain after and during penetrative sex
  • Stomach pain
  • Bleeding or spotting between periods
  • Gastrointestinal symptoms like diarrhea, nausea, constipation, and bloating, especially during menstruation

Symptoms of fibroids include:

  • Menstrual bleeding severe enough to cause anemia
  • A feeling of fullness in the pelvis and lower abdomen
  • Swollen or enlarged lower abdomen
  • Frequent urination
  • Complications during labor and delivery, including a higher risk for cesarean section (C-section, the surgical deliver of the baby)

Can You Have Both Endometriosis and Fibroids?

A 2021 review of studies published in Frontiers of Reproductive Health found that fibroids and endometriosis commonly occur together. Exact data about the frequency of comorbidity (the simultaneous presence of both conditions) can vary among studies and is not clearly defined.

Endometriosis starts to develop at a much earlier age than fibroids. There is no specific evidence indicating that endo causes fibroids. However, it may be a risk factor.

Polycystic Ovary Syndrome: Another Potential Diagnosis

Polycystic ovary syndrome (PCOS) can accompany endometriosis and fibroids or present overlapping symptoms with those conditions. This hormonal disorder is earmarked by the presence of excess androgens (sex hormones such as testosterone). It causes ovulatory (egg release) dysfunction and missed or irregular periods. It can also cause the formation of cysts on the ovaries.

Diagnostic Testing for Endometriosis vs. Fibroids

Symptom overlap and the potential for comorbidity may make getting a diagnosis challenging. Imaging and other tests can help your healthcare provider determine your condition.

Your healthcare provider will ask about your symptoms and medical history. They'll also ask about gynecologic conditions that run in your family.

A pelvic exam will be performed to look for signs of fibroids, endometrial cysts, and endometrial scar tissue.

Several diagnostic tests can be used to make a definitive diagnosis of fibroids:

  • Abdominal and vaginal ultrasound: This noninvasive test uses sound waves to view the uterus, ovaries, and other internal structures.
  • Sonohysterography (also called saline infusion sonogram, or sonohysterogram): This ultrasound test provides visual information about your uterine lining, fallopian tubes, and ovaries. It uses a thin, flexible catheter to inject saline solution through the cervix into the uterus.
  • Magnetic resonance imaging (MRI): This test uses strong magnets and radio waves to provide a detailed picture of fibroids' size, location, and number.
  • Hysteroscopy: This test uses a telescopic instrument to view and identify submucosal fibroids and polyps.

These imaging tests can help uncover evidence of endometriosis but don't provide enough information for a definitive diagnosis. Ultrasounds can miss flat and small endometrial lesions. Ultrasounds also can't determine if tissue growth is endometrial or of some other origin.

Ultrasounds can, however, be used to rule out fibroids, indicating that endo is the more likely diagnosis.

Surgery to Diagnose Endometriosis 

Endometriosis can only be diagnosed definitively through a surgical procedure, such as a laparoscopy. Laparoscopic surgery is the most common procedure for this purpose.

Endometriosis severity is categorized from stages 1 to 4. Laparoscopy is also used to determine what stage of endo you have.

During this minimally invasive procedure, your surgeon will make one or more small incisions in your lower abdomen. A thin tube with a camera will be inserted through an incision.

Your surgeon will use the camera to view your reproductive organs and to look for endometriosis lesions, adhesions, and scar tissue. A tissue sample (biopsy) may be taken and sent to a laboratory to be viewed under a microscope.

Treatment Variations in Endometriosis vs. Fibroids 

Treatment for both conditions can help reduce symptoms, such as pain, that interfere with your quality of life. Asymptomatic disease does not always require treatment.

However, your symptoms may not represent your condition's severity. Many people find out they have fibroids, endo, or both when they try to get pregnant and can't. In these instances, treatment can be beneficial for supporting conception and pregnancy.

Treatments for endometriosis may halt or slow down the progression of the disease. Untreated endometriosis can spread throughout the reproductive tract, affecting the ovaries and fallopian tubes. It can also spread to the bladder and bowels.

Endometriosis treatments include:

  • Hormonal birth control (pills, shots, intrauterine devices): This first-line treatment reduces the impact of hormones on endo symptoms. It is used in people who are not currently trying to conceive.
  • Gonadotropin-releasing hormone (GnRH) agonists: This short-term medical treatment improves symptoms by inducing temporary menopause. It can be used by people who wish to get pregnant.
  • Laparoscopy: Surgical procedures are used when hormonal treatments are not enough to reduce symptoms or restore fertility. One of the benefits of getting a diagnostic laparoscopy for endometriosis is the ability to be treated simultaneously. Your surgeon may remove all or most of the endometrial-like lesions, adhesions, and scar tissue found during the diagnostic procedure.
  • Laparotomy: This major form of surgery is less commonly used for endometriosis. It may be needed in instances where the spread is severe.

Treatment for fibroids is based on symptom severity and your wish for pregnancy. The size of the fibroid and its location are pivotal factors to consider if you wish to get pregnant. In some instances, your healthcare provider may recommend watchful waiting. You'll undergo imaging tests regularly to determine if your fibroids are getting bigger.

Fibroid treatments for symptoms like pain and heavy bleeding include hormonal forms of birth control. They're used in people who at the time do not wish to get pregnant. In some instances, these treatments may stop fibroids from growing and provide symptom relief. However, they only work while they're being taken. Treatments include:

Your healthcare provider may recommend using gonadotropin-releasing hormone (GnRH) agonists for a short time. GnRH agonists are beneficial for shrinking fibroids. They may be used before surgery to make fibroid removal easier. They may also temporarily halt menstruation in people with iron deficiency anemia who get very heavy periods because of fibroids.

Fibroids that interfere with conception or cause severe symptoms may be surgically removed. Like endometriosis, fibroids tend to grow back over time after surgical removal. Any of several surgical procedures may be recommended for fibroid removal:

  • Myomectomy: Removes fibroids but leaves healthy uterine tissue intact
  • Myolysis: Fibroids are destroyed by electrical current or freezing
  • Hysterectomy: Removes the entire uterus, is the only full cure for fibroids, and eliminates the possibility of pregnancy
  • Endometrial ablation: Removes or destroys the uterine lining (endometrium) and eliminates the possibility of pregnancy
  • Uterine fibroid embolization and uterine artery embolization: Block off the fibroids' blood supply, causing it to shrink

Coping With Chronic Pain

Pain is an unfortunate side effect of many conditions, including endometriosis and fibroids. Dealing with chronic pain may require a multifaceted approach that consists of medical treatments and self-care. Alternative treatments, such as acupuncture, may also be helpful for reducing pain.

Pelvic floor physical therapy is another alternative treatment that may reduce muscle irritation and pain in the pelvic floor. A specially trained physical therapist will do internal and external work on short or tight muscles in that area to reduce discomfort.

Minor pain may be reduced or alleviated with over-the-counter medications, such as ibuprofen or acetaminophen.

Stress management strategies, including yoga and meditation, may enable you to better cope with pain. Activities that bring you joy can also help reduce stress. These range from spending time with friends to walking your dog to taking hikes in beautiful surroundings.

Self-care, like getting enough sleep, exercising, and eating healthy food, can also be helpful for pain management.


Endometriosis and fibroids are two distinct conditions that can occur together. Both conditions may be asymptomatic, or cause symptoms that range from mild to severe. When symptoms do occur, they can include severe pain, bleeding, and infertility. Treatments exist that can provide symptom relief.

16 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By Corey Whelan
Corey Whelan is a freelance writer specializing in health and wellness conntent.