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Causes of Endometriosis

Endometriosis is an incurable but manageable gynecological condition. It occurs when endometrial implants, comprised of tissue normally found within the uterus, are present in other areas of the body. As the tissue continues to thicken, break down, and bleed during the menstrual cycle, it becomes trapped within the body. Scar tissue and adhesions form, and this can cause organ fusion and anatomical changes. Endometriosis is thought to affect around 11 percent of women in the United States (U.S.) aged between 15 and 44 years.


Although the exact cause of endometriosis is not certain, possible explanations include:

  • Retrograde menstruation. In retrograde menstruation, menstrual blood containing endometrial cells flows back through the fallopian tubes and into the pelvic cavity instead of out of the body. These displaced endometrial cells stick to the pelvic walls and surfaces of pelvic organs, where they grow and continue to thicken and bleed over the course of each menstrual cycle.
  • Transformation of peritoneal cells. In what's known as the "induction theory," experts propose that hormones or immune factors promote transformation of peritoneal cells — cells that line the inner side of your abdomen — into endometrial cells.
  • Embryonic cell transformation. Hormones such as estrogen may transform embryonic cells — cells in the earliest stages of development — into endometrial cell implants during puberty.
  • Surgical scar implantation. After a surgery, such as a hysterectomy or C-section, endometrial cells may attach to a surgical incision.
  • Endometrial cells transport. The blood vessels or tissue fluid (lymphatic) system may transport endometrial cells to other parts of the body.
  • Immune system disorder. It's possible that a problem with the immune system may make the body unable to recognize and destroy endometrial tissue that's growing outside the uterus.
  • Family history: women who have a close relative with the condition are up to 7-10 times more likely to get endometriosis. Also, it is common with twins that both may get endometriosis, particularly if they are identical twins

Other possible factors that may have a role in causing endometriosis are:

  • having first pregnancy at an older age
  • heavy bleeding during periods and periods lasting longer than five days
  • regularly having less than 27 days between periods, or having shorter regular cycles
  • low body weight


Here are some key points about endometriosis:

  • Endometriosis affects between 6 and 10 percent of women of reproductive age worldwide.
  • The condition appears to be present in a developing fetus, but estrogen levels during puberty are thought to trigger the symptoms.
  • Most women go undiagnosed, and in the U.S. it can take around 10 years to receive a diagnosis.
  • Endometriosis is not contagious.

Allergies, asthma, chemical sensitivities, autoimmune diseases, chronic fatigue syndrome, fibromyalgia, breast cancer, and ovarian cancer are linked to women and families with endometriosis.

How do you know if you have endometriosis?

The symptoms vary from woman to woman. Some women have many symptoms and severe pain, whereas others have no symptoms. About a third of women with endometriosis discover they have it because they have not been able to become pregnant, or because endometriosis is found during an operation for another reason. The type of symptoms and their severity are likely to be related to the location of the endometrial tissue rather than the amount of endometrial cells growing.

Endometriosis is a chronic condition with no cure. But this doesn’t mean the condition has to impact your daily life. Effective treatments are available to manage pain and fertility issues, such as medications, hormone therapy, and surgery.