What Is Endometriosis?

Endometriosis occurs when the tissue that lines your uterus, the endometrium, grows outside your uterus, usually in the area of your ovaries, fallopian tubes and the ligaments that support the uterus. Endometriosis can be extremely painful, because the tissue, even though it's not in its correct place in your body, continues to develop into growths or lesions which thicken, break down, bleed and shed with each menstrual cycle. Where normal tissue flows through your vagina during your menstrual cycle, this tissue becomes trapped – it has nowhere to go. This leads to internal bleeding, inflammation and can cause extreme pain, infertility and bowel issues.
Endometriosis affects more than 6 million women in the United States.

What Causes Endometriosis?

The exact cause of endometriosis isn't clear, however there are several reasons why endometriosis might develop.

  • Retrograde menstruation: this happens when menstrual blood flows backwards into the fallopian tubes and pelvic cavity. The endometrial cells in this blood attach to the pelvic organs and the pelvic wall, where they continue to grow.
  • Embryonic cell growth: sometimes the embryonic cells that make up the lining of the abdominal and pelvic cavities develop into endometrial tissue, causing endometriosis.
  • Surgical scars: endometrial cells may attach to a surgical incision following procedures such as Cesarean-sections or hysterectomies.
  • Endometrial cell transport: endometrial cells can be transported to other parts of the body through the lymphatic system.
  • Genetics: there is a possibility that endometriosis is an inherited condition. Girls with a close relative who has endometriosis are more likely to develop the condition themselves.
  • Hormones: estrogen stimulates endometriosis.
  • Immune system disorder: if the body's immune system isn't working properly, it may not recognize and destroy the endometrial tissue living outside the uterus. 

What are the Symptoms of Endometriosis?

Endometriosis is chronic and produces pain during the menstrual cycle that is far worse than normal and increases in severity over time. Women with endometriosis may experience the following symptoms:

  • Pain before and during menstrual periods that is more severe than normal.
  • Pain during sex.
  • Pain during bowel movements or while urinating.
  • Excessive bleeding during your menstrual cycle.
  • Infertility.

Diagnosis of Endometriosis

Once you report your symptoms to your physician, your doctor will take a detailed history and may have you undergo a series of tests which may include:

  • Pelvic exam.
  • Ultrasound.
  • Laparoscopy.

Once a detailed diagnosis is reached, your physician will determine the best treatment options for you.


Suneeta Senapati, MD, MSCE, assistant professor of obstetrics and gynecology at the Hospital of the University of Pennsylvania, discusses the impact of endometriosis on women's fertility and how it can be managed better to reduce the burden of infertility.

Penn Programs & Services for Endometriosis

Reproductive Surgery

A treatment option to correct anatomical disorders that affect reproductive function

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