Endometriosis is a condition in which the tissue that
normally lines the inside of the uterus is found outside
the uterus. This tissue is known as the endometrium.
The uterus is a hollow organ in a female's body where
the egg is implanted and the baby develops. In
endometriosis, even though the endometrial tissue is
located outside of the uterus, it still grows and bleeds
as it would if it were inside the uterus during a
A period (also known as the menstrual cycle) is the shedding of the lining of the uterus
that generally occurs once every 28 days in women who are not pregnant.
WHERE IS ENDOMETRIOSIS USUALLY FOUND?
As mentioned above, endometriosis is defined by endometrial tissue being outside of the
uterus. Sometimes, pieces of endometrial tissue are found on ligaments attached to the
uterus. A ligament is a tough band of tissue that attaches to joint bones. Endometrial
tissue may also attach itself to the outside of the fallopian tubes. Fallopian tubes are two
structures that serve as passageways from the ovary to the uterus. The ovaries are a
pair of sex glands that contain the eggs (female reproductive cells) and produce female
hormones. Hormones are natural chemicals produced by the body and released into the
blood that have a specific effect on tissues in the body.
Endometriosis may also present as a cyst on the ovaries, since bits
of endometrial tissue may attach itself to the them. A cyst is an
abnormal lump, swelling, or sac that contains fluid, a part solid
material, or a gas, and is covered with a membrane. A membrane is
a thin layer of flexible tissue that covers something.
Endometriosis can also occur on the surface of the vagina, bowel,
or bladder, but this is more uncommon than the other areas
Wherever the pieces of endometrial tissue occur outside of the
uterus, they may form scars known as adhesions.
WHAT ARE SIGNS AND SYMPTOMS OF ENDOMETRIOSIS?
The most common signs and symptoms of endometriosis are pain and increased bleeding. The pain is
most common just prior to the menstrual period or in the first few days during it. The pain is usually mild,
but is severe in some cases. Some women experience back pain when having intercourse or when having
a bowel movement. Symptoms generally get worse over time.
In some cases, there are no signs and symptoms, which is why many women either never know they have
the condition or do not find out until they go to the doctor to discover why they cannot get pregnant.
Endometriosis leads to increased rates of infertility, which is the inability to produce offspring.
HOW COMMON IS ENDOMETRIOSIS?
Endometriosis is a common condition, occurring mostly in women who are in their 30s or 40s. The
condition can also occur in adolescence, however. It has been estimated that about 10 to 20% of females
ages 15 to 45 have endometriosis. Some estimates for this age range are as low as 3 to 10%. The
reason why the exact number is unknown is because many women do not have symptoms.
WHAT CAUSES ENDOMETRIOSIS?
At present, the cause of endometriosis is unknown. One possibility is that the blood produced by the
menstrual cycle backs up through the fallopian tubes, much like water backs up in a clogged sink. When
this happens, endometrial tissue cells may be carried outside the uterus. Once this happens, the
endometrial tissue may attach itself to the structures discussed above.
Hormones appear to play a role in endometriosis, as there is evidence that estrogen promotes this
disease. Estrogen is a type of hormone that promotes the growth of some physical female sexual
characteristics. Another possibility is that there is something wrong with the body's immune (defense)
system that allows the endometrial tissue to grow outside the uterus. There may also be a genetic
component to endometriosis, since the condition is more likely in women whose mothers also have it.
HOW IS ENDOMETRIOSIS DIAGNOSED AND TREATED?
Endometriosis may be suspected based on the person's symptoms, but is diagnosed through a
laparoscopy. A laparoscopy is a surgical procedure (done under general anesthesia) in which a thin
viewing instrument known as a laparoscope is inserted into the abdomen (belly) through a small incision
made by (or in) the belly-button. The laparoscope can also be used as a surgical instrument to remove a
tissue sample. A biopsy is then performed, in which the tissue is analyzed under a microscope. This helps
to check for cancer cells. Fortunately, endometriosis is rarely cancerous.
Endometrial tissue outside the uterus can usually be removed during the laparoscopy by cutting it out or
burning it with additional instruments. Mild cases may not require treatment. However, women with
moderate or severe symptoms may require surgery and/or medication (that is, hormone therapy). Surgical
removal of endometrial tissue may not solve the problem because the tissue can grow back in some
Unfortunately, some women develop extensive endometriosis with masses that can be as large as a
grapefruit. In such cases, a procedure known as a laparotomy is required to gain access to a larger area
to remove the tissue. A laparotomy is a procedure that involves exploration inside the abdomen after a
large single cut through the abdominal tissue.
There are several hormonal treatment options available, which aim to reduce the level of estrogen in the
body and/or decrease excessive bleeding. As mentioned above, many believe that estrogen promotes
endometriosis and so decreasing it should help reduce symptoms. Birth control pills are commonly used
for this purpose. Progestins are the mostly commonly used medications, which work by suppressing the
normal cycle of the ovary. This, in turn, interferes with the menstrual cycle. Progestins also help treat
endometriosis by thinning the lining of the uterus. An example of a commonly used progestin is Provera.
Another group of hormonal treatments are gonadotropin-releasing hormone agonists (GnRH), such as
Lupron, Synarel, and Zoladex. GnRH is normally released from the brain and stimulates the body to
produce estrogen. An agonist is a type of medication that promotes a response (as opposed to
antagonists, which block responses). Thus, a GnRH agonist promotes the release of GnRH. This massive
increase of GnRH overwhelms the body and causes the ovaries to shut down estrogen production.
Doctors used to prescribe a medication known as Danazol to reduce estrogen levels and stop women
from having their period. But the medications described above are usually used these days, as Danazol
has been known to have some very unpleasant side effects. However, other medications mentioned
above also have potential serious side effects, so it is helpful to research treatment issues carefully.
In cases where endometriosis returns after surgery and medication treatment, the doctor may recommend
removal of the uterus and/or ovaries. Surgical removal of the uterus is known as a hysterectomy. Surgical
removal of the ovaries is known as an oophorectomy. Removing the uterus helps with pain relief. Removal
of the ovaries eliminates the production of hormones that may stimulate endometriosis to occur. One
serious consequence of removing either the uterus or ovaries is that child-bearing will no longer be
WHAT ELSE IS ENDOMETRIOSIS KNOWN AS?
Endometriosis is also known as endometrial implants.
WHAT IS THE ORIGIN OF THE TERM, ENDOMETRIOSIS?
Endometriosis comes from the Greek word "endon" meaning "within," the Greek word "metra" meaning
"uterus," the Greek word "trophe" meaning "a turning," and the Greek word "osis" meaning "condition." Put
the words together and you have "within uterus turning condition."