Endometriosis is a common disorder that affects women of reproductive age. Most women who have endometriosis experience few or no symptoms. However, some patients who have endometriosis experience pain or infertility, painful periods or pain with intercourse. Proper treatment of endometriosis depends on an accurate diagnosis.

The Uterus

The uterus (or womb) is a hollow organ situated in the middle of the pelvis. The bottom of the uterus is connected by its cervix to the vagina. The two fallopian tubes are attached to the top of the uterus. Eggs are stored in the nearby ovaries and released monthly at the time of ovulation. The ovaries also produce the hormones estrogen and progesterone.

The uterus is composed mostly of muscle and fibrous tissue. The inside of the uterus, however, is lined by several layers of special cells, called the endometrium. The endometrium responds to estrogen and progesterone, preparing for the implantation of a pregnancy.

The Menstrual Cycle

The cycle of hormone production by the ovaries have two phases. The first half of the cycle is called the follicular phase. During the follicular phase an egg matures within the ovary, surrounded by a collection of hormone-producing cells. Together the egg, fluid and surrounding cells are called a follicle. Follicles secrete estrogen into the blood stream. Estrogen circulates to the uterus and stimulates the lining (endometrium) to grow. Thus, while the ovary is in its follicular growth phase, the endometrium is in a proliferative phase.

Ovulation occurs at mid cycle. An egg is released from the ovarian follicle and travels toward the fallopian tube where it may be fertilized. The emptied follicle transforms into what is called the corpus luteum. During the second half of the cycle, the corpus luteum produces progesterone. Progesterone causes the endometrium to accumulate nutrient materials and ready itself to receive a fertilized egg. While the ovary produces progesterone in the (corpus) luteal phase of the cycle, the endometrium is in a secretory phase.

If pregnancy fails to occur, the production of hormones from the ovary will fall ten days to two weeks after ovulation. Without the stimulation of estrogen and progesterone the endometrium deteriorates. The lining of the uterus crumbles; bleeding begins. Menstrual discharge contains blood, tissue fragments and the chemical products of endometrial cells.

What is Endometriosis?

Endometriosis is characterized by the presence of uterine lining tissue (endometrium) outside of the uterus.

How Does Endometriosis Progress?

Endometriosis usually begins as flat patches on the ovaries or ligaments of the pelvis. These patches of mild endometriosis may spontaneously disappear over a period of months or they may remain unchanged.

At other times, the endometriosis may progress. Bloody fluid released from these patches may coalesce into cystic collections within the ovaries. Old blood darkens to a deep red-brown or tarry color-giving rise to the description “chocolate cysts.” Chocolate cysts may be as small as a marble or as large as a grapefruit!

If blood and debris leak out of an endometriosis cyst, a woman may notice sudden pain. Spilled endometriosis may also cause inflammation and the development of scar tissue. The moderate stages of endometriosis are characterized by ovarian (chocolate) cysts and scar tissue.

In its severe stages, endometriosis may glue uterus, tubes, ovaries and nearby intestines into a matted mass. The endometriosis may spread into the walls of the intestine or into the tissue that partitions the rectum from the vagina.

Who is Likely to Develop Endometriosis?

It has long been observed that endometriosis shrinks during pregnancy. The high and continuous progesterone level of pregnancy is thought to be responsible. Hormone therapies that simulate pregnancy are often effective against endometriosis. In light of pregnancy’s therapeutic effect, it is not surprising that advanced endometriosis is more likely to be found in women who have deferred pregnancy. For this reason endometriosis has gotten a reputation as a “career woman’s disease.” However, the condition may affect teenagers or women who have had children.

Predictably, with the drop in estrogen that accompanies menopause, endometriosis regresses. Modeling on nature, hormone therapies that create a temporary menopause-like state have proven effective against endometriosis.


Painful Periods

Prostaglandins and other irritating substances in menstrual blood cause painful periods (dysmenorrhea). In addition, an obstruction to menstrual flow through the cervix (cervical stenosis) can increase pressure in the uterus and result in crampy pain. The release of inflammatory substances from endometriosis tissue in the ovaries or pelvis may intensify cramping pain at the time of menstruation. Even though the endometriosis is located outside the uterus, the pain that it causes is not distinguishable from uterine cramping. As the disease progresses, a woman may experience pain that is more and more severe or occurs before and after the menstrual flow.

Not every woman who experiences painful periods has endometriosis. Moreover, some patients with endometriosis have no pain with their periods. It is a puzzling feature of endometriosis that the pain it causes is not always in proportion to the amount of endometriosis tissue present in the pelvis. Certain features of painful periods suggest endometriosis. An increase in the intensity or duration of cramping may indicate progressing endometriosis. Cramping which begins several days before the menstrual flow is also suggestive of endometriosis.

Various medical treatments are available for painful periods. Oral contraceptives often reduce or eliminate cramping. Anti-inflammatory drugs such as aspirin or ibuprofen may decrease cramping as well. The response of cramping to oral contraceptives or anti- inflammatory drugs does not distinguish women with endometriosis from those with other causes of dysmenorrhea. While helping the pain, these drugs do not reliably halt the progression of the disease.


Women with endometriosis may have trouble conceiving. The ways in which endometriosis cause infertility are not completely understood. Endometriosis within the pelvis may irritate surrounding tissue, leading to damage by scarring of the tubes and/or ovaries. Growth of scar tissue called adhesions may attach ovaries, tubes, ligaments and intestines together in unnatural ways. If the ovaries are pulled away from the tubes, eggs will not enter the tubes after ovulation. If the tubes are damaged the fertilized egg may not be able to pass into the uterus in a timely fashion.

Even endometriosis that is located at a distance from the tubes and ovaries may impair fertility. Substances released from pelvic endometriosis may travel to the ovaries and interfere with ovulation or implantation.

For a particular woman with endometriosis it may be impossible to decide whether the extent of her disease is sufficient to predict or explain difficulty getting pregnant. Endometriosis must be seen in the context of other factors effecting fertility, such as quality of sperm, conditions present at the cervix and the process of ovulation.

Pain with Intercourse

The ovaries are normally suspended in the pelvis by ligaments, free to move back and forth. Scar tissue (adhesions) caused by endometriosis may attach the ovaries to the uterus or pelvis. The thrusting motion of intercourse may bruise these fixed ovaries. Collections of endometriosis at the base of the pelvis near the vagina may also give rise to pain during and after intercourse.

Irregular Bleeding

Occasionally, endometriosis is accompanied by unusually heavy menstrual bleeding or by bleeding at irregular intervals. Most women with endometriosis, however, continue to have normal flows at regular intervals.

Miscarriage and Birth Defects

About 15 percent of all pregnancies end in miscarriage. In cases of untreated extensive endometriosis, the rate of miscarriage may be increased. For women whose endometriosis has been treated, the miscarriage rate seems to be the same as for women without endometriosis. There is no evidence linking the presence of endometriosis to birth defects. Care may be necessary, however, to avoid conception while a woman is receiving hormonal treatment for endometriosis. These hormone preparations could affect a developing fetus adversely.

Unusual Manifestations

Rarely, pockets of endometriosis may exist in the wall of the bladder, the intestines, surgical scars or even the lungs. During menstruation, these pockets may release blood into urine, bowel movements or sputum.


Painful periods, painful intercourse and infertility suggest the presence of endometriosis. However, these symptoms may be present in patients without endometriosis; and, patients with endometriosis may be without symptoms. Therefore, the diagnosis cannot be made on the basis of symptoms alone.

Certain features of a physical and pelvic examination suggest endometriosis. These findings are more easily appreciated when the exam is done during menstruation. Patches of endometriosis tissue may be visible on the external genitalia, within the vagina or on the cervix. A uterus that is both tipped backwards and held fixed by adhesions often indicates the presence of endometriosis. Enlarged ovaries, especially if fixed in place, suggest but do not guarantee that endometriosis is present.

The finding on pelvic examination that is most characteristic of endometriosis is lumpiness (or nodularity) along the ligaments that hold the uterus in place. These ligaments are best examined by the combined vaginal and rectal examination. While the findings of a pelvic examination may make a physician suspicious of endometriosis, a definite diagnosis cannot be made on the basis of the examination.

Diagnostic Tests

Ultrasound is often used to help diagnose endometriosis. Endometriosis cysts in the ovary have a unique texture, raising a high suspicion of the disease. The common x-ray visualization of the uterus, called hysterosalpingogram, does not pick up the condition. Likewise, biopsy of the uterine lining (endometrial biopsy) is not helpful.

No blood tests currently distinguish endometriosis from other causes of ovarian enlargement and fixation of pelvic organs. Extensive cases of endometriosis may cause positive readings on blood tests currently used to screen or follow patients with ovarian cancer, even though no cancer is present.


Having obtained a careful history, performed a thorough examination and utilized ultrasound, a physician must still resort to direct visualization of the pelvic contents in order to be sure that endometriosis is present. This visualization is done by means of diagnostic laparoscopy. A laproscope is a fiber-optic tube that is inserted through a small incision hidden near the belly button. Laparoscopy is usually performed under general anesthesia, on an outpatient basis and takes less than one hour to be completed. Looking through a laproscope, a surgeon sees the outer surface of the uterus, tubes and ovaries, as well as the other contents of the pelvic-abdominal cavity. Sometimes, the surgeon may drain collections of fluid, eliminate endometriosis with laser or electricity and cut away scar tissue at the time of diagnostic laparoscopy. Thus, laparoscopy identifies the presence and extent of endometriosis and, in some cases, allows for immediate therapy.


Mild cases of endometriosis which do not cause symptoms may not require active intervention since these small patches often remain stable or even disappear.

Hormonal treatment of endometriosis has been modeled on natural events that are known to inhibit endometriosis—pregnancy and menopause. As in pregnancy and menopause, the hallmark of effective treatment for endometriosis is absence of menstruation. If the lining of the uterus is suppressed, so is the endometriosis.

In an effort to reproduce the hormone environment of pregnancy, oral contraceptives have been prescribed in a special fashion to women with endometriosis. When used to prevent pregnancy, the active oral contraceptive pills are taken for three weeks followed by a one-week hiatus to allow for a menstrual flow. Oral contraceptives taken in this fashion will often control painful periods but are not a recognized treatment for endometriosis. Oral contraceptives taken on a continuous basis without a pause for withdrawn bleeding are more likely to reduce the amount of endometriosis tissue. Continuous administration of oral contraceptives is associated with side affects which include nausea, water retention and break through bleeding as well as rare, but much more serious complications such as stroke, vascular problems and heart disease.

Continuous progesterone administration (also to mimic pregnancy) has been used as a treatment for endometriosis. Pill forms of synthetic progesterone may be effective, but are accompanied by a high incidence of breakthrough bleeding. Stronger injectable forms of progesterone are available but not presently sanctioned by the Federal Drug Administration (FDA) as a treatment for endometriosis.

The synthetic hormone danazol is another medication available for the treatment of endometriosis. Danazol is a weak male-type hormone that interferes both with the production of hormones by the ovary and with the way that endometriosis responds to hormones. Danazol is a pill that is taken at least twice a day. Side effects include water retention, weight gain, acne, breakthrough bleeding, and muscle cramps. Danazol is usually better tolerated than continuous oral contraceptives and is likely to be effective for many women. It is administered from 3-12 months at a time, depending on the extent of the disease. It is quite effective in controlling pain and eliminating small patches of the disease. Large cystic collections of endometriosis are generally resistant to danazol treatment.

The most frequently employed medical treatment for endometriosis utilizes medications with “GnRH”- like effects, for example Lupron. These drugs work by turning off the stimulation of the ovaries which normally comes from the pituitary gland. As a result, estrogen and progesterone levels drop to a level similar to those of a child. Endometriosis tissue shrinks and may disappear. Large cystic collections of endometriosis are rarely eliminated in this fashion. Side effects of GnRH agonists reflect a lack of estrogen. These include vaginal dryness, pain with intercourse, hot flashes and loss of calcium from the bone. GnRH-like drugs are given by injection, or nasally or subcutaneous implants. A course of treatment typically lasts between 3-6 months. In order to moderate side effects of low estrogen, a small amount of estrogen replacement may be “added back” in pill form.

Surgical Treatment

Medical treatment of endometriosis will usually control pain and eliminate small patches of active endometriosis. Large collections of cystic fluid are not as responsive to medication. Medication cannot dissolve scar tissue and adhesions resulting from the inflammation of endometriosis. Surgery is usually the best way to treat endometriosis to improve fertility.

Most endometriosis surgery is performed using the laparoscope. Occasionally, a full incision is necessary when the disease is advanced.

Fertility Treatment

Women known to have endometriosis are often treated with fertility drugs, artificial insemination and/or in vitro fertilization. These treatments may be successful even when some endometriosis tissue remains within the patient.

More Extensive Surgery

For women beyond child bearing age, or in who endometriosis is exceedingly advanced, removal of the uterus, tubes and/or ovaries is an option. After both medical and conservative surgical treatment, it is possible the endometriosis will return. Removal of both ovaries as well as the uterus lowers the chance of recurrence to a minimum. Just how much of the pelvic organs should be removed in an endometriosis procedure is a matter to be individualized on a case to case basis. Removal of the ovaries leaves women in an estrogen-deficient state. Women who have undergone removal of the ovaries for endometriosis may usually be treated with estrogen replacement therapy successfully.

Endometriosis affects millions of women throughout the world. In many endometriosis neither causes pain nor affects fertility. For the majority the condition goes unnoticed. Other women experience pain or infertility with this unpredictable disease. To help cope with endometriosis support groups have arisen. Examples include Resolve, an infertility-oriented group with chapters throughout the USA. Endometriosis Societies are also organized in the U.S., Canada and Great Britain. These groups provide information and emotional support, which may be as critical as medicine or surgery to the woman with endometriosis.