In endometriosis, cells that look and act like the endometrial cells (from the endometrium, the tissue that lines the uterus) implant on pelvic organs outside of the uterus, often on the fallopian tubes, ovaries and bowels. This endometrial tissue outside of the uterus responds to hormonal changes—it thickens and sheds as part of menstruation. But because it has nowhere to go, it builds up and causes inflammation of surrounding tissue.

Over time, this can cause damage, scarring, lesions and adhesions, which are abnormal sections of fibrous tissue that cause organs to stick together.

Woman hiker gazing at her surroundingsWoman hiker gazing at her surroundingsWoman checking in for clinic visit

Symptoms of endometriosis

Endometriosis symptoms vary widely. The severity of symptoms does not always indicate how advanced or widespread the endometriosis is. Some people may have only minor lesions but excruciating pain. Others may have minor endometriosis symptoms but advanced scar tissue.

The most common symptom of endometriosis is pelvic pain that gets worse with a menstrual period. However, other symptoms might include:

  • Back pain, which can occur at any point during the menstrual cycle.
  • Constipation or diarrhea.
  • Extremely painful periods (dysmenorrhea). Women with endometriosis often describe having extreme cramps that make it difficult to move. These pains often start a few days before the period and continue afterward.
  • Fatigue, or an intense feeling of tiredness that doesn’t go away with rest.
  • Heavy bleeding with periods, or bleeding in between periods (intermenstrual bleeding).
  • Lower abdominal pain, which sometimes starts a week or more before a period.
  • Nausea and bloating, which may get worse closer to a period.
  • Pain or discomfort while urinating or having a bowel movement. This pain usually starts before and gets worse during a menstrual period
  • Pain while having penetrative sexual intercourse. This pain can range from stabbing to a dull ache deep within the abdomen. Penetration can stretch and pull on scar tissue and endometrial growths around the vaginal canal and in the pelvis.

These symptoms do not always mean you have endometriosis. However, if you do have symptoms, you should speak to your women’s care specialist so you can get the right diagnosis and treatment.

How is endometriosis diagnosed?

If you experience symptoms of endometriosis, you should talk to your healthcare provider or gynecologist. They will ask you some questions about your family and medical history. The following methods may be used to help your doctor rule out other conditions and diagnose endometriosis.

Laparoscopy. Laparoscopic surgery is a minimally invasive surgical procedure, where your surgeon makes a small incision in your abdomen and inserts a small tube with a light and camera. This allows your healthcare provider to clearly see the extent and location of misplaced endometrial tissue.

Pelvic exam. A gynecologist manually feels areas of your pelvis for signs of abnormalities, cysts and scar tissue.

Ultrasound. This involves inserting an ultrasound wand into the vagina or pressing it against your belly. The ultrasound scan can show ovary cysts (endometriomas), scar tissue and other markers of endometriosis.

Other imaging exams. Your doctor may also recommend an MRI or CT scan. These imaging exams create detailed images of your internal organs, bones and muscles, and they can help find the underlying cause of your symptoms.

Get an expert diagnosis. Getting your endometriosis properly diagnosed isn’t always straightforward. Many women with endometriosis are initially dismissed by providers who are not familiar with the disease, and don’t know what to look for. We will work with you to get the correct diagnosis and best plan of care for your unique needs.

Endometriosis treatment

Endometriosis varies from person to person. So too does treatment. Depending on the severity of your symptoms, treatment for endometriosis involves some combination of surgery and medications. Sometimes, it can take some trial and error to find the right combination for you.

Hormone therapy medications

Hormone therapy medications are often the first line of treatment for endometriosis. This is because endometriosis is related to, and often made worse by, the hormonal fluctuations of a normal menstrual cycle.

  • Hormonal contraceptives. Hormonal contraceptives like hormonal intrauterine devices (IUDs) and birth control pills are often used to treat endometriosis. These medications work by stopping hormones from fluctuating, which prevents ovulation (the release of an egg) but also stops the misplaced endometrial cells from growing and shedding. While hormonal contraceptives do not cure endometriosis, they are generally effective at reducing endometriosis symptoms. However, some people find that the side effects of hormonal contraceptives (weight gain, mood fluctuations, headaches and more) interfere with their daily life. You may need to try different types or formulations of contraceptives to find one that works for you. Additionally, hormonal contraceptives prevent pregnancy, so they are not a good choice for people looking to become pregnant.
  • Gonadotropin-releasing hormone agonists (GnRH agonists). These drugs block the production of estrogen, the main hormone that stimulates the ovaries and causes the menstrual cycle. Lowering estrogen levels essentially shuts off the menstrual cycle and prevents the endometriosis tissue from growing and shedding. However, because these medications induce artificial menopause, they can come with side effects like weight gain, hot flashes, vaginal dryness and bone loss. Your doctor may recommend you take a low dose of estrogen and progesterone to reduce these side effects.

Fertility treatment

As noted, endometriosis can impact your fertility and make it challenging to start a family. And the main treatment for endometriosis, hormone therapy, generally makes it impossible to get pregnant. However, you may be a candidate for a fertility treatment like in vitro fertilization (IVF). IVF is a procedure in which an egg is removed from your body and fertilized externally, in a lab setting. The fertilized egg is then implanted in your uterus and allowed to grow. IVF allows you to bypass any damage to the fallopian tubes and still carry a pregnancy successfully. Not everyone is a good candidate for IVF, but if you are struggling to start a family, you should talk to one of our experts.


  • Conservative surgery. If you are trying to get pregnant, or if your endometriosis does not respond to hormone therapy, you may be a candidate for conservative surgery. In this approach, surgeons remove the endometrial implants but preserve as much of the uterus, fallopian tubes and ovaries as possible. Your surgeon will likely perform laparoscopic (minimally invasive) surgery, where your surgeon makes a small incision in your abdomen and inserts a small tube with a light and camera, allowing them to see the extent and location of endometriosis lesions and cysts. This tissue is then removed or vaporized by a precise laser. After surgery, your doctor may recommend hormone medications to help ease pain and prevent a flare-up. However, endometriosis can come back after surgery.
  • Hysterectomy and oophorectomy.
    A hysterectomy is the removal of the uterus. Removing the uterus can help ease some of the symptoms of endometriosis, like severe cramps and menstrual periods. Sometimes, a hysterectomy is combined with an oophorectomy, or removal of the ovaries. The ovaries drive the menstrual cycle, and removing them means that the hormonal fluctuations of a normal cycle stop. This means that misplaced endometrial tissue stops growing and shedding. However, removing the ovaries causes early menopause, which can cause hot flashes, weight gain and vaginal dryness. Removing the uterus and ovaries can have long-term health consequences, especially if the patient is less than 35 years old. Additionally, for some people, endometriosis and its symptoms persist even after the uterus and ovaries have been removed. Women who have their uterus and ovaries removed cannot get pregnant. If you are considering a hysterectomy and/or oophorectomy, you may want to get a second opinion about your treatment options before consenting.

Endometriosis complications

Endometriosis and infertility

Endometriosis is the leading cause of infertility in women. As many as half of all women with endometriosis struggle to conceive. When endometriosis involves the ovaries, cysts (endometriomas) can form. These cysts damage the ovaries and can lead to infertility. They often require surgical treatments. Additionally, scarring and tissue damage to the fallopian tubes can prevent the fertilization of an egg or the movement of a fertilized egg to the uterus.

However, many people who have endometriosis can successfully conceive and carry a healthy pregnancy. If you suspect you have endometriosis and want to get pregnant, you should talk with your gynecologist to explore your risks, options and ways to maximize your chance of success.

Endometriosis and pregnancy complications


A miscarriage is when there is a spontaneous pregnancy loss prior to the 20th week of the pregnancy. Endometriosis may increase the risk of a miscarriage, although the exact reason for this is not clear. There is no way to prevent a miscarriage.

Ectopic pregnancy

An ectopic pregnancy is a pregnancy that occurs outside of the uterus, usually in the fallopian tubes. An ectopic pregnancy is a dangerous and sometimes life-threatening medical condition. Embryos cannot successfully grow outside of the uterus and may rupture the fallopian tube or damage other organs. Endometriosis increases the risk for an ectopic pregnancy, because scar tissue in the fallopian tubes can prevent the movement of a fertilized egg to the uterus. There is no way to prevent or save an ectopic pregnancy. They require immediate medical attention.

Preterm labor

Endometriosis can also increase your risk for preterm or early labor, or labor that occurs before 37 weeks of pregnancy. Premature birth can impact the baby’s health, as critical organs like the lungs are still developing.

In general, having endometriosis increases your risk for complications during pregnancy. If you have endometriosis and you are trying to get pregnant, you should talk to your doctors about your risks, options and concerns. If you do become pregnant, be sure to see your doctor so that you can monitor the pregnancy closely.

Endometriosis: risk factors and possible causes

Risk factors

Risk factors for endometriosis include:

  • Being age 30 to 40.
  • Having a first-degree relative (mother, sister or daughter) who has endometriosis.
  • Having an abnormally shaped uterus.
  • Having short menstrual cycles (27 days or shorter).
  • Having a condition that interferes with menstrual flow.
  • Not having birthed a child, or giving birth for the first time after age 30.
  • Starting your period before age 12.

Possible causes

The cause of endometriosis is not clear, but research is ongoing. Some experts think it may be the result of retrograde menstruation, which is when tissue shed during a menstrual period backs up into the fallopian tubes and moves into the abdomen. These tissue cells then implant in the pelvis and beyond.

Endometrial tissue could also be misplaced during or after surgery, like a hysterectomy (removal of the uterus) or C-section. Some studies suggest that various hormonal, genetic and immune factors cause cells in the pelvis to transform into endometrium-like cells. Research is also ongoing into whether the immune system plays a role in endometriosis.

Is it endometriosis or something else?

The symptoms of endometriosis can resemble those of other conditions, like irritable bowel syndrome (IBS), polycystic ovarian syndrome (PCOS) and pelvic inflammatory disease (PID). These conditions also cause symptoms like pelvic pain, heavy periods and bowel movement problems. Additionally, these conditions can occur alongside endometriosis, further complicating diagnosis.

The best way to get an accurate diagnosis is to see a gynecologist who specializes in endometriosis and similar issues. However, there are a few things you can keep in mind when you go see your doctor:

Endometriosis vs. PCOS

These are both conditions that can cause heavy periods and trouble getting pregnant. However, while endometriosis is related to estrogen and progesterone, PCOS is related to a hormone called androgen. Common PCOS symptoms that differ from endometriosis symptoms include:

  • Dark, thickened skin.
  • Missed or irregular periods.
  • Excess body hair.
  • Acne and oily skin.

Endometriosis and PCOS can occur together.

Endometriosis vs. IBS

Irritable bowel syndrome (IBS) is a group of intestinal symptoms that occur together. It can cause abdominal pain, constipation and diarrhea, cramping, bloating and gas. While these symptoms do overlap with endometriosis, they are usually caused by spasms in the large intestine or imbalances in the gut bacteria. IBS does not cause heavier periods. However, endometriosis and IBS can occur together, and IBS symptoms may worsen during menstruation.

Endometriosis vs. adenomyosis

Adenomyosis is a condition in which endometrial tissue grows into the muscular lining of the uterus. The misplaced endometrial tissue responds to hormonal changes, building up and breaking down in much the same way. This can lead to an enlarged uterus and painful menstrual periods.

The main difference between endometriosis and adenomyosis is the location of the endometrial cells. In endometriosis, the cells are outside the uterus. In adenomyosis, the cells are still inside the uterus, just in the wrong layer. Adenomyosis responds to many of the same treatments as endometriosis. Unlike endometriosis, it can be cured by fully removing the uterus (hysterectomy). The two conditions sometimes occur together.

Endometriosis vs. pelvic inflammatory disease

Pelvic inflammatory disease (PID) is an infection that affects the reproductive organs, causing inflammation and pain within the pelvis. It is commonly caused by sexually transmitted infections (STIs) like chlamydia and gonorrhea, but it can also be caused by other non-sexually-transmitted infections that get into the uterus during menstruation or childbirth.

PID and endometriosis have many of the same symptoms, such as severe lower abdominal pain, nausea and painful urination. However, PID symptoms often include fever and foul-smelling vaginal discharge. Antibiotics or antiviral medications can usually help with PID, although these drugs do not reverse tissue damage caused by the infection.

Outlook for patients with endometriosis

Endometriosis is a serious condition that is often
mis- or under-diagnosed. Beyond the diagnosis, endometriosis can affect many things, like your ability to be intimate with a partner, your ability to have a family and your overall quality of life.

At UCHealth, you can find services to address these challenges. We know that finding an empathetic and expert care team to help you through your treatment is essential to managing endometriosis and living a healthy, enjoyable life—and we are here to help.


The Office on Women’s Health (OWH). Endometriosis (https://www.womenshealth.gov/a-z-topics/endometriosis)

MedlinePlus: National Library of Medicine. Endometriosis (https://medlineplus.gov/endometriosis.html)

National Center for Biotechnology Information (NCBI): National Library of Medicine. Endometriosis (https://www.ncbi.nlm.nih.gov/books/NBK567777/)