Endometriosis and polycystic ovary syndrome (PCOS) are conditions that affect females of reproductive age. Both conditions can be painful and disrupt a normal menstrual cycle by causing excessive bleeding or irregular periods.

At least 1 in 10 females in the United States has endometriosis, while PCOS affects as many as 5 million females of reproductive age in the U.S.

Endometriosis is a condition where tissue that resembles the lining of the uterus grows outside of the uterine cavity, such as on the ovaries, bowel, or the tissues lining the pelvis.

PCOS is a condition that affects a female’s hormone levels. Females with PCOS have higher levels of “male hormones,” known as androgens. These interfere with ovulation and can cause excess hair growth and acne.

Insulin resistance is also common in women with PCOS, where the body does not respond properly to insulin. This can result in higher insulin and blood sugar levels and weight gain.

While both conditions have some similar symptoms, they also present with unique and distinct symptoms that help to differentiate between the two.

Read this article to learn more about the symptoms of endometriosis and PCOS and the differences between the conditions.

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People with endometriosis and PCOS share some symptoms such as heavy bleeding and difficulty getting pregnant. But each condition has unique symptoms. Some people with either condition present with no symptoms.

According to the National Institute of Child Health and Human Development (NICHD), symptoms of endometriosis and PCOS include:

Doctors do not fully understand the exact causes of both endometriosis and PCOS. However, researchers have found some possible causes.

Endometriosis causes

Some theories of possible causes of endometriosis include:

  • Retrograde menstruation: This theory suggests that some of the tissue that the body sheds during the menstrual cycle flows through the fallopian tube into other areas of the body, such as the pelvis.
  • Lymphatic or vascular system spread: Another theory suggests endometrial tissue may spread to distant organs and implant via blood or lymphatic channels (glands and tubes that form part of the immune system).
  • Coelomic metaplasia: This theory proposes that cells in the body outside of the uterus undergo changes to become endometrial-like tissue and start to grow.
  • Stem cells: This theory suggests that certain stem cells may be responsible for regenerating endometrial tissue in the menstrual cycle, and these stem cells may spread to other parts of the body, causing endometriosis.
  • Surgery: Another theory says that during certain surgical procedures such as a cesarean (C-section) or a hysterectomy, there could be accidental displacement of endometrial tissue.

PCOS causes

According to the NICHD, a possible cause of PCOS may be due to genetics.

PCOS can run in families, so it may result from a mutation in one or more inherited genes. Doctors have noted an increased prevalence among females with PCOS whose sisters and mothers also have the condition.

Certain risk factors can increase the chance of getting endometriosis or PCOS. People with endometriosis or PCOS are also at risk of developing other conditions.

Endometriosis risk factors

According to the NICHD, risk factors for a person having endometriosis include:

  • infertility
  • starting periods before age 11
  • having periods that last longer than 7 days
  • menstrual cycles lasting less than 27 days
  • a family history of endometriosis

A study from 2017 suggests a potential association with endometriosis in people with a lean body size.

PCOS risk factors

According to the Centres for Disease Control and Prevention (CDC), risk factors for PCOS include a family history of PCOS (such as a mother, aunt, or sister having the condition)

People with PCOS are at an increased risk of diabetes. More than half of females with PCOS develop type 2 diabetes by age 40.

Other conditions that people with PCOS are at risk of include:

A doctor can use several tests to determine if an individual has endometriosis or PCOS.

Endometriosis diagnosis

Doctors can only definitively confirm a diagnosis of endometriosis via laparoscopy surgery. This type of surgery is where a doctor inserts a small viewing instrument (laparoscope) into the abdomen to check the internal organs for endometriosis tissue.

However, they may make a presumptive diagnosis on the basis of patient history along with physical exams and imaging tests. A person does not need a definitive diagnosis to begin treatment for endometriosis.

During the diagnosis process, a health professional will discuss a patient’s medical history to assess symptoms and rule out other conditions. They may also use the following tests:

  • Pelvic exam: A physician will use this test to feel for cysts or scars behind the uterus.
  • Imaging test: A doctor will use an ultrasound or MRI scan to check for larger areas of endometriosis, such as cysts or nodules.
  • Medication: If a doctor does not notice any cysts, they may prescribe hormonal birth control. If the person’s pain decreases while taking this medication, they may have endometriosis.

PCOS diagnosis

A doctor usually makes a diagnosis of PCOS if they have ruled out other conditions and a person displays some of the following symptoms:

  • irregular or infrequent periods (signaling an absence of ovulation)
  • high levels of androgens (a doctor confirms these with blood tests or noting physical signs such as excess hair growth on the face and body, acne, and thinning hair)
  • multiple cysts on one or both ovaries

A healthcare professional may diagnose PCOS with any of the following tests:

  • Physical exam: During a physical exam, a doctor will determine a person’s blood pressure, body mass index (BMI), and waist size. They will also examine a person’s skin for extra hair on the face, chest, or back.
  • Pelvic exam: A physician may perform a pelvic exam to detect signs of high levels of male hormones, including an enlarged clitoris. They may also check if a person has enlarged ovaries.
  • Pelvic ultrasound: This test uses sound waves to examine ovaries for cysts and to check the lining of the uterus.
  • Blood test: A doctor will use this test to determine if a person has high levels of androgens. They may also check hormones associated with an underactive thyroid to rule out these conditions.

Yes, women can have endometriosis and PCOS, although they rarely occur together.

A recent review of research on both conditions suggests that endometriosis occurs in 7–8% of females with PCOS and is usually mild.

People with a PCOS diagnosis should talk with their doctor if they notice bodily changes or symptoms associated with endometriosis.

There is no cure for endometriosis or PCOS, but there are treatment options for both conditions in terms of managing symptoms and fertility.

Endometriosis treatment

Treatment options for symptoms of endometriosis include:

  • pain medication
  • hormone therapy, including hormonal birth control (if not trying to get pregnant)
  • surgery, including laparoscopy and hysterectomy (removal of the uterus)
  • lifestyle changes, such as quitting smoking, eating a more nutritious diet, and exercising more to help with pain management

Healthcare professionals may recommend laparoscopy surgery to people with endometriosis, depending on how severe the condition is, in order to improve fertility.

If a person is still struggling to get pregnant after surgery, a doctor may recommend in vitro fertilization (IVF).

PCOS treatment

Treatment options for PCOS are usually for symptom management. These include:

  • acne or hair-loss medication
  • lifestyle changes, such as exercise and weight loss
  • hormonal birth control
  • anti-androgen medication
  • hair removal
  • insulin-sensitizing agents, such as metformin
  • weight management
  • pain medication

Fertility problems for people with PCOS usually occur from an absence of ovulation. According to the American College of Obstetricians and Gynecologists, lifestyle changes such as losing weight can trigger more regular periods in people with PCOS.

A healthcare professional may recommend a person lose weight before trying medication for infertility associated with PCOS.

A doctor may prescribe medications such as letrozole, clomiphene, and metformin to help a person with PCOS experiencing infertility.

Individuals should speak with a doctor if they have any of the following symptoms:

  • pelvic pain
  • very painful periods
  • heavy menstrual bleeding
  • irregular periods
  • pain during or after sexual intercourse
  • difficulty getting pregnant

Endometriosis and PCOS can negatively affect a person’s quality of life.

A person can manage both of these conditions with lifestyle changes and medications, but symptoms do not go away completely, meaning they will likely have symptoms their whole life.

That is why it is important for a person to speak with a healthcare professional if they suspect they have one of these conditions.

The sooner a person receives a diagnosis, the sooner they can begin treatment and improve their symptoms.