The endometrium is the tissue lining the inside of the uterus and it is responsible for menstruation. Endometriosis is a gynecological disorder characterized by the presence of endometrial tissue outside the uterus, either on the ovaries, the fallopian tubes, or the ligaments supporting the uterus, or on neighbouring organs such as the bladder and intestine.

Like the endometrium, endometrial lesions are sensitive to hormones and bleed during a woman's period. This bleeding can irritate the peritoneum, which is the membrane lining the inside of the abdomen. Over time, scars can form on the fallopian tubes and ovaries, restricting their mobility. The scar tissue can prevent the release of the ovum and disrupt transportation of the fertilized egg, making the woman infertile.

Most women have what is known as "retrograde menstruation" - i.e. a portion of their menstrual tissue flows back through the fallopian tubes to the abdominal cavity. Some women are unable to eliminate this, and it ends by implanting itself and forming endometrial lesions. There is a genetic predisposition to endometriosis. In other words, if your mother or sister have or have had endometriosis, you have a greater chance of having the same disorder.

Symptoms are not related to the size of the lesions. Typically, progressive pain is experienced during menstruation and sexual relations, but some women experience no symptoms whatsoever.

During the gynecological examination, it may be found that the uterus has turned backwards (retroversion), there are painful nodules on the ligaments suspending the uterus, and sometimes ovarian cysts can be discovered. Although the gynecological examination and some ultrasound images may give reason to suspect endometriosis, the diagnosis must be confirmed by laparoscopy.

The gynecologist can generally perform surgery during the laparoscopy. This requires introducing two to four extra tubes into the abdomen and then removing the endometrial lesions using electrocautery or a laser. The adhesions can then be freed and the ovarian cysts removed, so that the patient's anatomy reverts to normal.

Further treatment will depend on the patient's specific symptoms. Surgical treatment can be followed or preceded by medical treatment. The principle of medical treatment is to prevent hormone stimulation of the endometrium. Oral contraceptives can be used, progesterone agents and other more specific medications. Cyclomen (Danazol) is a synthetic hormone that blocks secretion from the ovaries and produces artificial menopause. It has side effects such as weight gain, hot flashes and acne. LHRH analogues (Lupron, Zoladex, Synarel) are more modern medications that block the pituitary gland and also prevent the production of estrogen, like during menopause. These medications are mainly useful when there is associated pain. No study has shown any increase in fertility following medical treatment; on the contrary, as most of these treatments block ovulation, patients cannot conceive during treatment which can last from three to six months.

Thirty-eight percent of women with infertility problems actually have endometriosis. In some cases, only small, isolated lesions are found, with no anatomical distortion. A Canadian study (Endocan) has shown substantially higher levels of pregnancy following cauterization of small stage I and II endometrial lesions that did not affect the anatomy of the fallopian tubes and ovaries.

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