Overview and Risk Factors
Endometriosis is a common condition in which implants of endometrial tissue appear outside of the uterine cavity, usually within the pelvis. It is a frequent cause of dysmenorrhea and pelvic pain, and it may cause infertility. The pathogenesis is unknown but is thought to be associated with retrograde menstruation, in which menstrual tissue flows through the fallopian tubes and into the pelvic and abdominal peritoneum. Other hypotheses suggest the condition may result from displacement of endometrial tissue through surgical processes (eg, cesarean section, episiotomy), transport of cells through blood or lymph to distant locations, and differentiation of peritoneal cells to become endometrial cells.
Endometriosis is largely dependent upon active menstruation. The disease rarely occurs prior to menarche or after menopause. The most commonly involved locations are the peritoneal surface of the ovaries, anterior and posterior cul-de-sac, and the pelvic ligaments. In the gastrointestinal tract, the sigmoid colon and the appendix are most commonly affected. In some cases, the vagina and urinary system can be involved.
The severity of the condition varies greatly. It can be asymptomatic or severe and even debilitating. Symptoms are often nonspecific and do not always correlate with the severity of disease. Common symptoms include pelvic, abdominal, or low-back pain occurring in the premenstrual or perimenstrual period; abnormal uterine bleeding; dyspareunia; and infertility. Further symptoms occur based on the location of ectopic endometrial tissue (eg, rectal bleeding or pain with defection if colonic lesions are present, suprapubic pain upon urination if bladder lesions are present). Most women with endometriosis have no symptoms, and many women with severe pain have minimal visible endometriosis, suggesting that the body's response to the implants is more important than the presence of the implants themselves.
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% in first-degree relatives. Dietary factors may play a role and are discussed in Nutritional Considerations below.
Endometriosis is usually suspected from the history, although tender nodules and masses may be palpable or visible on the vagina or cervix during pelvic examination.
Many gynecologists believe that definitive diagnosis can be made only by laparoscopic visualization of lesions and/or biopsy. Endometrial implants may appear in various colors (black, red, yellow, white, blue, or clear). If a visual diagnosis is in question, a biopsy that reveals endometrial glands and stroma is considered diagnostic. As most endometriosis is asymptomatic and many women with typical endometriosis symptoms have no visible disease, an alternative view is that endometriosis is better diagnosed by history, physical examination, and response to therapy than by surgical visualization.
Endoscopy of the colon or cystoscopy may reveal implants of the sigmoid or proximal colon and bladder.
Elevated serum CA-125 concentration suggests the presence of the condition, and higher values may correspond with advanced disease. CA-125 can also be followed to evaluate response to medical treatment.
Imaging studies are not usually of value, although an ultrasound may be used to detect bulky disease such as endometriomas, which may benefit from surgical removal.
The treatment strategy depends upon the severity of disease, proximity to menopause, and whether the patient hopes to become pregnant. After menopause, symptoms will likely improve dramatically, even in severe disease.
Analgesics (eg, NSAIDs) and oral contraceptive pills are indicated for pain relief. Oral contraceptives may also reduce the risk of ovarian cancer.1
Gonadotropin-releasing hormone (GnRH) analogs, danazol, or progestins (eg, norethindrone acetate, intrauterine levonorgestrel) may be very helpful. GnRH analogs (eg, nasal nafarelin, leuprolide injections, goserelin implants) decrease ovarian estrogen production, preventing the pain-inducing stimulation of ectopic endometrial tissue. Treatment usually lasts at least 6 months. These agents cause a temporary decrease in bone density that has not been shown to be clinically important. Supplemental estrogen or norethindrone acetate may minimize the side effects of hot flashes and bone mineral loss.
Medical therapy affords long-term relief in about 50% of patients. Surgery is often used for severe or intractable disease, although it has not been proven superior to medical therapy. Laser ablation or electrocautery of endometrial implants and adhesions may treat the pain, decrease the rate of recurrence, and restore fertility. If there is no desire for future pregnancy, definitive treatment is total abdominal hysterectomy with bilateral salpingo-oopherectomy. However, most patients can be managed effectively without such extreme measures.
Endometriosis is an estrogen-dependent disorder,2 and some studies have suggested that oxidative stress may contribute to the disease process.3 These observations may explain the apparent value of diet and exercise interventions, which can improve both hormone levels and antioxidant status. Conversely, alcohol may increase the risk for endometriosis through its documented tendency to increase both estrogen level and oxidative stress. The following factors have been shown in epidemiologic studies to be associated with 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, case-control studies have suggested that frequent red meat and ham consumption is associated with endometriosis risk, while fruit and vegetable intake appears to be protective. In an Italian population including 504 cases and an equal number of matched controls, women who ate at least 7 servings of red meat per week had twice the risk of endometriosis compared with those who ate fewer than 3 servings of red meat weekly. Women having 13 or more servings per week of green vegetables had a 70% lower risk of endometriosis compared with those ate fewer than 6 servings per week. And those eating 14 or more servings of fruit per week had a 20% lower risk compared with women having fewer than 6 servings per week.4 Second, women with higher fiber intake and lower intake of fatty foods have reduced estrogenic activity,5 a change that may be beneficial in this population but has not as yet been tested (See Dysmenorrhea chapter.)
Exercise. Women who exercise have a much lower risk for endometriosis, and those who engage in frequent strenuous exercise have at least 75% lower risk for endometriosis, compared with those who do not engage in high-intensity activity.6
Avoiding alcohol. Compared with healthy women and women with other gynecological problems, women who drink alcohol appear to have a greater incidence of endometriosis.7 In women with infertility, the risk of endometriosis was 50% higher in individuals who drank alcohol compared with control subjects.8
What to Tell the Family
Endometriosis is a painful disorder that will frequently respond to available medical therapies. Regular exercise may improve symptoms. Alcohol consumption should be minimized. A low-fat, vegan diet, which is helpful for functional menstrual pain, has not been tested for endometriosis.
1. Zullo F, Palomba S, Zupi E, et al. Effectiveness of presacral neurectomy in women with severe dysmenorrhea caused by endometriosis who were treated with laparoscopic conservative surgery: A 1-year prospective randomized double-blind controlled trial. Am J Obstet Gynecol. 2003;189:5-10.
2. Giudice LC, Kao LC. Endometriosis. Lancet. 2004;364:1789-1799.
3. Van Langendonckt A, Casanas-Roux F, Donnez J. Oxidative stress and peritoneal endometriosis. Fertil Steril. 2002;77:861-870.
4. Parazzini F, Chiaffarino F, Surace M, et al. Selected food intake and risk of endometriosis. Hum Reprod. 2004;19:1755-1759.
5. Barnard ND, Scialli AR, Hurlock D, Bertron P. Diet and sex-horÂmone binding globulin, dysmenorrhea, and premenstrual symptoms. Obstet Gynecol. 2000;95:245-250.
6. Dhillon PK, Holt VL. Recreational physical activity and endometrioma risk. Am J Epidemiol. 2003;158:156-164.
7. Perper MM, Breitkopf LJ, Breitstein R, Cody RP, Manowitz P. MAST scores, alcohol consumption, and gynecological symptoms in endometriosis patients. Alcohol Clin Exp Res. 1993;17:272-278.
8. Grodstein F, Goldman MB, Cramer DW. Infertility in women and moderate alcohol use. Am J Public Health. 1994;84:1429-1432.