PCOS and Endometriosis: The Key Differences

PCOS and Endometriosis: The Key Differences

Polycystic ovary syndrome (PCOS) and endometriosis are two distinct conditions that can affect the reproductive system during reproductive years. While they both cause changes in menstruation and impact the ability to get pregnant, many of the symptoms and treatment options are different. 

Those struggling with PCOS have hormone imbalances that occur during their reproductive years. The condition causes the ovaries to produce more androgens (the “male” sex hormone) than is typically found in cisgender women. With PCOS, small sacs of fluid (called cysts) containing immature eggs develop along the outer edge of the ovary. When women don’t make enough hormones to ovulate, these cysts develop and create androgens, causing more problems with the menstrual cycle.

Endometriosis, on the other hand, is a medical condition where endometrial-like tissue (similar in structure to the tissue that lines the uterus and sheds during a period) is found outside of the uterus. The extrauterine endometrial-like tissue (lesions) are typically found in the pelvic cavity (on the bladder, rectum, or ovaries) as well as the bowel, diaphragm, and pleural cavity.


Most of the symptoms of PCOS and endometriosis are different. It’s also possible to have these conditions without any symptoms at all.

PCOS symptoms include:

-   Missed periods, irregular periods, or very light periods

-   Ovaries that are large or have many cysts

-   Hirsutism (excess body hair)

-   Weight gain, particularly in the abdomen

-   Acne or oily skin

-   Thinning hair

-   Infertility

-   Skin tags

-   Dark patches on skin (back of neck, armpits, under breasts)

Endometriosis symptoms include:

-   Painful periods

-   Painful sex

-   Painful bowel movements or urination

-   Excessive bleeding

-   Infertility

-   Fatigue

Other important differences:

  1. Prevalence:

PCOS affects 5 to 20 percent of women in their reproductive age, while endometriosis affects approximately 10 to 15 percent.

  1. Cause:

While the exact cause of PCOS and endometriosis are unknown, researchers say PCOS runs in families, and that insulin resistance and inflammation can play a role. John Hopkins says endometriosis may also have a genetic component, with other possible explanations being: blood or lymph system transport (where endometrial tissues are carried to other areas of the body, similar to the way cancer cells spread), direct transplantation (where endometrial cells attach to the walls of the abdomen or other areas of the body after surgery), or reverse menstruation (where the endometrial tissue goes into the fallopian tubes and abdomen instead of exiting the body during a period.)

  1. Diagnosis:

PCOS tends to be easier to diagnose than endometriosis, as it involves less invasive physical exams, including a sonogram to see cysts on the ovaries and blood tests to check hormone levels.

Endometriosis requires a laparoscopy to get a full medical diagnosis. Because of gender bias in medicine and the difficulty in diagnosing endometriosis, people with ovaries often suffer through many years of dismissed pain before being diagnosed.

  1. Treatment: 

For those trying to conceive with PCOS, a combination of medication, adjustments to nutrition and weight management can be used to manage symptoms and help trigger ovulation. For those not trying to conceive, birth control or diabetes medication can also be used to help reduce androgens. 

Endometriosis treatment can include birth control to reduce estrogen and regulate growth of endometrial tissue, pain medication for relief, surgical removal of tissue, and hysterectomy.


Both PCOS and endometriosis are common, and it is possible to have PCOS and endometriosis concurrently. Women often struggle to have their pain fully acknowledged in a medical setting (being prescribed more sedatives than men to treat “anxiety” rather than the actual root of their condition, for example).

If you are experiencing any symptoms related to PCOS and endometriosis, such as pain, light periods or heavy bleeding, and struggles to conceive, it’s important to reach out to a doctor who can administer the appropriate tests and find an effective treatment plan.

Advocating for oneself can be difficult, but you deserve for your chronic pain to be taken seriously. While there is no cure for PCOS or endometriosis, there are many techniques to help manage the symptoms.

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