Endometriosis is a disease that affects women globally and is characterized by a formation of tissue that lines the uterus (endometrium) outside of the uterus appearing in the wrong places such as the fallopian tube, pelvic cavity, or ovaries. This can cause extreme pain and affect fertility of women.

Endometriosis is classified from stage 1 to stage 4 according to the amount of endometrial tissue present and how widespread it is in the body. The severity of symptoms does not define the stage of the disease.

Endometrial-like tissue thickens, degrades and bleeds with each menstrual cycle just like the normal tissue but cannot flow out of the body. The pelvis and other body parts may develop scar tissue (adhesions, fibrosis) because of the persistent inflammatory reaction it generates.

If the endometrial-like tissue grows in the ovaries, cystic ovarian endometriosis or endometrioma occurs. If it grows in pelvic peritoneum, it is called superficial endometriosis. If found in the recto-vaginal septum, bladder, and bowel, it is called deep endometriosis. Endometriosis can also be found outside of the pelvis, but this is uncommon.

During the menstrual period, endometriosis can cause severe pain due to inflammation that is increased as well as adhesions and fibrosis. It can also cause fertility problems to arise. However, there are effective treatments to overcome all the problems.


All women of reproductive age are susceptible to endometriosis. Some symptoms may be noticeable, others may not be. Although symptoms are broad and can varies individually, it usually starts with increasing pelvic pain during menstrual period worse than the common menstrual cramps.

Symptoms of endometriosis include:

  • Painful periods. Also known as dysmenorrhea, is a severe menstrual cramp that start prior and continue for several days during the menstrual period. It is usually felt in the lower abdomen and lower back. In some, the discomfort prevents women to do normal activities.
  • Painful sexual intercourse. It is common for women with endometriosis to experience pain during or after the intercourse.
  • Painful bowel movements or urination. Endometriosis can affect the bladder which can cause pain or discomfort in bowel movements and urination particularly during menstruation due to inflamed tissues.
  • Abnormal bleeding. Women with endometriosis may experience spotting or intermenstrual bleeding in between periods. In some, it can cause a heavy period or excess bleeding.
  • Infertility. Endometriosis is often discovered unintentionally. It happens when a person who has difficulty getting pregnant, starts to explore possible treatments.
  • Other signs and symptoms. During periods, women may also experience feeling sick, diarrhea, constipation, nausea, abdominal bloating, depression, or anxiety.

The level of pain and the duration to which the symptoms are experienced cannot accurately predict the severity of endometriosis. Experts cannot determine the exact cause why some cases are severe, and some are not. Or why it is more painful for one but not for the other.

Endometriosis has a broad range of symptoms, often similar to other diseases. In some cases, it can coexist with other conditions which makes the diagnosis more difficult such as with irritable bowel syndrome (IBS). Similarity in symptoms include diarrhea, constipation, and abdominal cramping. With pelvic pain as a common symptom, endometriosis can disguise as pelvic inflammatory disease (PID) or ovarian cysts.

Women who experience symptoms of endometriosis should consult a healthcare provider for better diagnosis.


Endometriosis has no definite cause. Several hypothesis are:

  • Retrograde menstruation. Menstrual blood with endometrial cells exits the body through the cervix and vagina during normal periods. In retrograde menstruation, it can return through the fallopian tubes and into the peritoneal cavity instead of flowing out. The cells develop throughout each menstrual cycle. As it sticks through the surfaces of the pelvic walls and organs, it will continue to thicken and bleed. This will increase the chances that endometriosis will develop.
  • Transformation of peritoneal cells. Hormones or immunological factors activates peritoneal cells to change into endometrial-like cells. If the cells make it to the abdominal cavity, it can lead to endometriosis. This is known as the “induction theory”.
  • Embryonic cell transformation. Embryonic cells which are still in the early stages of formation can potentially turn into endometrial-like cells especially during puberty. Hormones like estrogen are the major contributor for its transformation.
  • Surgical scar implantation. Endometrial-like tissue can connect itself to an incision following surgery, such as hysterectomy or C-section.
  • Endometrial cell transport. Endometrial cells may travel in other areas of the body through the lymphatic system or bloodstream. Lymphatic system is a network of tubes and glands that compose the immune system.
  • Immune system disorder. Altered or impaired immunity can lead to inability of the body to find and to remove the endometrial-like tissue which has formed outside the uterus.

Risk factors

Development of endometriosis may come from different risk factors, such as:

  • Early menarche (period before age of 11)
  • Late menopause
  • Short menstrual cycles interval (less than 27 days)
  • Prolonged menstrual flow, longer than 7 days
  • Never been pregnant
  • Family history of endometriosis
  • High level of estrogen in the body
  • Low body weight
  • Condition that blocks the menstrual flow
  • Disorders of the reproductive tract

All menstruating women are susceptible to endometriosis. Typically, endometriosis appears few years after the start of menstruation. Signs and symptoms may vary for every individual. It can potentially become better during pregnancy and may resolve on its own during menopause.