Endometriosis is a common medical disorder in which some of the cells that normally make up the lining of the uterus (the endometrium) appear in other parts of the body, most commonly in the pelvis and abdomen. It is a frequent cause of painful menstrual periods and pelvic pain and may result in infertility.

The cause of endometriosis is unknown, but is thought to be associated with backward flow of menstrual tissue through the fallopian tubes and into the pelvis and abdomen.

Endometriosis is largely dependent on active menstruation. The disease rarely occurs before the onset of adolescence or after menopause.

Symptoms

The severity of the disease varies greatly from one person to another. It can be asymptomatic or severe, is sometimes debilitating. Symptoms are often nonspecific and do not always correlate with the severity of disease. Most women with endometriosis have no symptoms. However, here are symptoms that suggest endometriosis:

• Pelvic, abdominal, or low-back pain occurring during the premenstrual or menstrual period
• Abnormal menstrual bleeding
• Painful sexual intercourse
• Infertility
• Further symptoms occur based on the location of endometrial tissue (e.g., rectal bleeding may occur if endometriosis occurs in the colon; abdominal pain may occur if endometriosis occurs in the bladder).

Risk Factors

The risk factors for endometriosis are not well understood. It is most commonly diagnosed in women in their late 20s and early 30s, and the occurrence is increased by 7 percent in first-degree relatives. Dietary factors may play a role and are discussed in Nutritional Considerations.

Endometriosis: Diagnosis and Treatment

Diagnosis

• A medical history and a physical examination are the first steps. Tender nodules and masses may be felt or seen on the vagina or cervix during pelvic examination.
• Many gynecologists believe that definitive diagnosis can be made only by surgical visualization and/or biopsy. However, others believe that endometriosis is better diagnosed by history, physical examination, and response to therapy.
• Blood tests may suggest the diagnosis and can be used to follow the patient's response to medical treatment.
• Colonoscopy or cystoscopy (a test that visualizes the inside of the bladder) may reveal endometriosis in the colon and bladder.
• Ultrasound may be used to detect large areas of endometriosis that may require surgical removal.

Treatment

The treatment strategy depends on the severity of disease, proximity to menopause, and whether the patient hopes to become pregnant. After menopause, symptoms will likely improve dramatically without specific treatment, even in severe disease.

• Analgesics (e.g., acetaminophen (Tylenol) and ibuprofen) and oral contraceptive pills are used for pain relief. Oral contraceptives may also reduce the risk of ovarian cancer.
• Several medical therapies, including gonadotropin-releasing hormone analogs (e.g., nafarelin, leuprolide and goserelin), danazol, or progestins, may be helpful. Treatment usually lasts at least six months.
• Medical therapy affords long-term relief in about 50 percent of patients. Surgery is often used for severe disease, although it has not been proven superior to medical therapy. Laser therapy may treat the pain, decrease the rate of recurrence, and restore fertility. If there is no desire for future pregnancy, definitive treatment is a hysterectomy. However, most patients can be managed effectively without such extreme measures.
• Women who exercise have a much lower risk for endometriosis, and those who engage in frequent strenuous exercise have at least 75 percent lower risk for endometriosis, compared with those who do not engage in high-intensity activity.

Endometriosis: Nutritional Considerations

The following factors have been shown in epidemiologic studies to be associated with a reduced risk of endometriosis:

• A high-fiber, plant-based diet: Although research on the effectiveness of dietary approaches is limited, several lines of evidence support the use of plant-based diets.
  
  First, red meat may be a risk factor for endometriosis, while fruit and vegetable intake is protective. Women who eat at least seven servings of red meat per week appear to have twice the risk of endometriosis compared with those who eat fewer than three servings. Women who eat 13 or more servings per week of green vegetables have a 70 percent lower risk of endometriosis compared with those who eat fewer than six servings. And those who eat 14 or more servings of fruit per week had a 20 percent lower risk compared with women who eat fewer than six servings.
  
  Second, women with higher fiber intake and lower intake of fatty foods have reduced estrogen activity, a change that is likely to prove beneficial in patients with endometriosis. In a controlled research study of women with typical menstrual pain (not endometriosis), a low-fat vegan diet reduced both the duration and severity of pain. It has been suggested that such a diet is likely to be beneficial for endometriosis as well, but it has not been clinically tested.
• Avoiding alcohol: Compared with healthy women and women with other gynecological problems, women who drink alcohol appear to have a greater prevalence of endometriosis. In women with infertility, the risk of endometriosis was 50 percent higher in individuals who drank alcohol compared with those who did not.