Endometriosis
Introduction
For some women the menstrual cycle brings about monthly pelvic pain. This pain can be awful, but it also may be a symptom of endometriosis.
What is it?
Endometriosis is a disorder in women that can cause painful menstruation, chronic pelvic pain, painful intercourse, and possible infertility. The disorder may worsen over time, resulting in scarring to the ovaries and fallopian tubes and leading to decreased ability to get pregnant. In fact, 30% to 40% of patients with endometriosis are infertile. This is two to three times the rate of infertility in the general population.
What causes it?
No single theory seems to explain all cases of endometriosis. Several theories, however, have been postulated:
- The endometrial cells, which line the uterus, migrate from the uterus through the fallopian tubes into the pelvis. These cells implant on other pelvic organs and are stimulated by hormones released during menstruation. This can cause bleeding at these locations. Surrounding organs may then absorb the blood, leading to pain and inflammation. This theory fails to explain why women still have endometriosis after sterilization (sometimes called 'having their tubes tied') or after hysterectomy (removal of the uterus). It is possible that the endometrial tissue spreads from the uterus to the abdominal cavity through the lymphatic system or bloodstream instead of through the fallopian tubes.
- The cause may stem from an abnormality in the immune system that allows normally shed endometrial cells to attach and grow in other areas.
- The disease may be caused by a genetic birth defect as evidenced by its tendency to run in families.
- Tissue in the abdominal cavity may change into endometrial tissue as a result of repeated inflammation.
Who has it?
Endometriosis is a common problem in women of reproductive age (generally 18 to 44 years). In the United States, endometriosis is the third leading cause of gynecologic related hospitalizations and the leading cause of hysterectomy. It is often suspected when pelvic pain, painful intercourse, or infertility are noted. Because a surgical procedure is necessary to make a definitive diagnosis, the exact prevalence of endometriosis is unknown. It is estimated that 5.5 million women and girls in North America have endometriosis.
What are the risk factors?
Risk factors for endometriosis remain unclear. The disease appears to occur most often in women between the ages of 25 and 35 years. The problem is rarely noted after menopause. Women who have a first-degree relative with endometriosis have a higher risk of developing the condition. Women with a menstrual pattern of long, heavy, and frequent periods also seem to be at increased risk. It is believed that endometriosis may be more common in women of upper economic classes. This may be due to a delay in pregnancy, which may increase the risk of endometriosis. Other factors that may place women at increased risk for developing endometriosis are obstructed menstrual flow, irregularities in her genital tract, and increased time since last pregnancy. Exposure to environmental factors (e.g. chlorinated hydrocarbons, dioxin) has also been associated with endometriosis.
What are the symptoms?
Nearly one-third of the women who have endometriosis have no symptoms other than infertility. Others have varying degrees of symptoms, depending on the stage of the disease. The early stages or milder forms are frequently more painful than the later stages. This may be because the young endometrial tissue is more likely to undergo spasms, whereas the older endometrial tissue may simply 'burn out' and turn into inactive scar tissue. Some commonly associated symptoms include the following:
- Painful periods
- Premenstrual spotting
- Heavy menstrual periods
- Urinary urgency or painful urination
- Increased cramping during intercourse
- Pain deep in the pelvis during intercourse
- Pain during bowel movements or rectal bleeding
Diarrhea or rectal bleeding and a sense of rectal fullness at the time of menses are significant clues to the development of endometriosis.
How is it treated?
The severity of the disease, the woman's history of infertility, the intensity of her desire for pregnancy, and her age all play a role in determining what type of treatment is chosen. A complete hysterectomy (surgical removal of the uterus) is the treatment of choice in women who are past their reproductive age. Other surgeries, such as a laparoscopy (minor abdominal surgery) or laparotomy (major abdominal surgery), and fertility drugs, such as clomiphene, are used to restore fertility in women wishing to become pregnant. The goals of surgery are to relieve symptoms, restore fertility, remove endometrial lesions if possible, and to delay recurrence of the disease.
Hormone treatment is popular as an alternative to surgery; however, hormones are not proven to be effective in treating endometriosis but may help to prevent further growth of endometriosis. Many women have found symptom relief from combination therapy with estrogen and progesterone. Other medications available include danazol or gonadotropin-releasing hormone (GnRH) agonists. Doctors sometimes prescribe nonsteroidal anti-inflammatory agents, such as ibuprofen, to relieve pain associated with contraction of the uterus during menstruation.
Helping Yourself
Personal habits that relate to decreased body estrogen levels such as exercise and smoking have been associated with decreased risk for endometriosis. Aerobic exercise also strengthens pelvic floor muscles, leading to better tolerance of pelvic pain. Relaxation techniques have the ability to decrease anticipatory stress and anxiety associated with the occurrence of pelvic pain when the menstrual cycle begins. Factors that may decrease the risk of endometriosis include reduced menstrual cycling and suppression of estrogen by pregnancy, oral contraceptive use, and menopause.
What is on the horizon?
Studies are currently exploring the possibility of a genetic link for the development of endometriosis and for new medical treatments for pain related to endometriosis. Several different genes have been looked at as possibly being connected to the development of endometriosis. Each gene researched thus far has not been linked to the development of endometriosis. In addition to gene research, improvements in laser and laparoscopic surgeries are leading to better treatments of the condition.
New research has found a possible cause of infertility in some women with endometriosis. The finding appeared in the July 2003 issue of Endocrinology, a medical journal. The study found that some women who are infertile as a result of endometriosis lack molecules in their uterus that let the embryo attach to the uterine wall. Because the embryo cannot attach, a pregnancy cannot occur. The researchers also reported that a number of genes present in the uteri of women with endometriosis appear to be functioning inappropriately. Many of those genes identified in the study had not been shown previously to contribute to endometriosis and the infertility that often accompanies the condition.
A large research project called The Oxford Endometriosis Gene (OXEGENE) Study was initiated in 2001 and was completed in 2005. The study was designed to determine which genes are involved in the development of endometriosis. The study involves hospitals and endometriosis self-help groups throughout the world. The study used sisters with surgically diagnosed disease of endometriosis in Australia and the United Kingdom. There appears to be a linkage between endometriosis and chromosome 10q, specifically chromosome 10q26. Further studies are planned to be conducted to confirm the results of this study as well as further research on genes PTEN and EMX2 which may also be linked to endometriosis.
A recent study has looked at the use of anastrozole (a drug used in the treatment of breast cancer) in the treatment of endometriosis. It is believed that endometric lesions produce estrogens. Anastrozole works by blocking an enzyme in the body called aromatase, causing decreased production of estrogen. While the study was promising, further studies are needed before considering anastrozole both safe and effective in endometriosis treatment. A recent study with letrozole, another drug that blocks aromatase, was stopped early because women developed ovarian cysts while taking the drug.
References
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Endometriosis.org Web site. Available at: http://www.endometriosis.org/. Accessed May 23, 2005, June 1, 2006, April 9, 2007, and March 25, 2008.
Information about the Oxford Endometriosis Gene Study Available at: http://www.medicine.ox.ac.uk/ndog/oxegene/info.htm. Accessed May 23, 2005, June 1, 2006, and April 9, 2007.
Lieu CL. Endometriosis. In : DiPiro JT, Talbert RL, Yee GC and others, eds. Pharmacotherapy: A Pathophysiologic Approach. 6th ed. New York: McGraw-Hill; 2002: 1485-1491.
MayoClinic.com. Endometriosis. Available at: http://www.mayoclinic.com/health/endometriosis/DS00289. Accessed April 9, 2007 and March 25, 2008.
Medscape. Aromatase Inhibitors and Endometriosis. Available at: http://www.medscape.com/viewarticle/473018. Accessed May 23, 2005 April 9, 2007, and March 25, 2008.
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Schenken RS. Endometriosis. In: Scott JR, DiSaia PJ, Hammond CB, Spellacy WN, eds. Danforth's Obstetrics and Gynecology. 8th ed. Philadelphia: Lippincott, Williams & Wilkins; 1999.
National Institute of Child Health and Human Development. Endometriosis. Available at: http://www.nichd.nih.gov/health/topics/Endometriosis.cfm. Accessed April 9, 2007 and March 25, 2008.
Treloar SA, Wicks J, Nyholt DR, et al. Genomewide Linkage Study in 1176 Affected Sister Pair Families Identifies a Significant Susceptibility Locus for Endometriosis on Chromosome 10q26: Am.J.Hum.Genet. 2005;77:365-76.
Endometriosis Health Condition Last Updated: March 2008
Note: The above information is intended to supplement, not substitute for, the expertise and judgment of your physician, pharmacist, or other healthcare professional. It is not intended to diagnose a health condition, but it can be used as a guide to help you decide if you should seek professional treatment or to help you learn more about your condition once it has been diagnosed.