What is endometriosis?
Endometriosis is the growth of cells similar to those that form the inside of the uterus
(endometrial cells), but in a location outside of the uterus. Endometrial cells are the same
cells that are shed each month during menstruation. The cells of endometriosis attach
themselves to tissue outside the uterus and are called endometriosis implants. These
implants are most commonly found on the ovaries, the Fallopian tubes, outer surfaces of the
uterus or intestines, and on the surface lining of the pelvic cavity. They can also be found in the vagina, cervix, and bladder, although less commonly than other locations in the pelvis. Rarely,
endometriosis implants can occur outside the pelvis, on the liver, in old surgery scars, and
even in or around the lung or brain. Endometrial implants, while they can cause problems, are
benign (not cancerous).
Who is affected by endometriosis?
Endometriosis affects women in their reproductive years. The exact prevalence of
endometriosis is not known, since many women may have the condition and have no
symptoms. Endometriosis is estimated to affect over one million women (estimates range
from 3% to 18% of women) in the United States. It is one of the leading causes of pelvic pain
and reasons for laparoscopic surgery and hysterectomy. While most cases of endometriosis
are diagnosed in women aged around 25-35 years, endometriosis has been reported in girls
as young as 11 years of age. Endometriosis is rare in postmenopausal women.
Endometriosis is more commonly found in white women as compared with African American
and Asian women. Studies further suggest that endometriosis is most common in taller, thin
women with a low body mass index (BMI). Delaying pregnancy until an older age is also
believed to increase the risk of developing endometriosis.
What causes endometriosis?
The cause of endometriosis is unknown. One theory is that the endometrial tissue is
deposited in unusual locations by the backing up of menstrual flow into the Fallopian tubes
and the pelvic and abdominal cavity during menstruation (termed retrograde menstruation).
The cause of retrograde menstruation is not clearly understood. But retrograde menstruation
cannot be the sole cause of endometriosis. Many women have retrograde menstruation in
varying degrees, yet not all of them develop endometriosis.
Another possibility is that areas lining the pelvic organs possess primitive cells that are able to
grow into other forms of tissue, such as endometrial cells.
It is also likely that direct transfer of endometrial tissues during surgery may be responsible for
the endometriosis implants sometimes seen in surgical scars (for example, episiotomy or
Cesarean section scars). Transfer of endometrial cells via the bloodstream or lymphatic
system is the most likely explanation for the rare cases of endometriosis that develop in the
brain and other organs distant from the pelvis.
Finally, some studies have shown alternations in the immune response in women with
endometriosis, which may affect the body's natural ability to recognize and destroy any
misdirected growth of endometrial tissue.
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What are endometriosis symptoms?
Most women who have endometriosis, in fact, do not have symptoms. Of those who do
experience symptoms, the common symptoms are pain (usually pelvic) and infertility. Pelvic
pain usually occurs during or just before menstruation and lessens after menstruation. Some
women experience pain or cramping with intercourse, bowel movements and/or urination.
Even pelvic examination by a doctor can be painful. The pain intensity can change from month
to month, and vary greatly among women. Some women experience progressive worsening
of symptoms, while others can have resolution of pain without treatment.
Pelvic pain in women with endometriosis depends partly on where the implants of
endometriosis are located:
Deeper implants and implants in areas with many pain-sensing nerves may be more likely to
produce pain.
The implants may also produce substances that circulate in the bloodstream and cause pain.
Lastly, pain can result when endometriosis implants form scars. There is no relationship
between severity of pain and how widespread the endometriosis is (the "stage" of
endometriosis).
Endometriosis can be one of the reasons for infertility in otherwise healthy couples. When
laparoscopic examinations are performed for infertility evaluations, endometrial implants can
be found in some of these patients, many of whom may not have painful symptoms of
endometriosis. The reasons for a decrease in fertility are not completely understood, but
might be due to both anatomic and hormonal factors. The presence of endometriosis may
involve masses of tissue or scarring (adhesions) within the pelvis that may distort normal
anatomical structures, such as Fallopian tubes, which transport the eggs from the ovaries.
Alternatively, endometriosis may affect fertility through the production of hormones and other
substances that have a negative effect on ovulation, fertilization of the egg, and/or implantation
of the embryo.
Other symptoms related to endometriosis include:
• lower abdominal pain,
• diarrhea and/or constipation,
• low back pain,
• irregular or heavy menstrual bleeding, or
• blood in the urine.
Rare symptoms of endometriosis include chest pain or coughing blood due to endometriosis
in the lungs and headache and/or seizures due to endometriosis in the brain.
How is endometriosis treated?
Endometriosis can be treated with medications and/or surgery. The goals of endometriosis
treatment may include pain relief and/or enhancement of fertility.
Endometriosis at A Glance
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Endometriosis is the growth of endometrial tissue (cells that normally grow inside the
uterus (womb), but in a location outside of the uterus. Endometriosis is most commonly
found on other organs of the pelvis. |
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The exact cause of endometriosis has not been identified. |
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Endometriosis is more common in women who are experiencing infertility than in fertile
women, but the condition does not fully prevent conception. |
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Most women with endometriosis have no symptoms, in which case therapy is neither
appropriate nor necessary. |
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Pelvic pain during menstruation or ovulation can be a symptom of endometriosis, but
may also occur in normal women. |
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Endometriosis can be suspected by the practitioner by the woman's pattern of
symptoms, and sometimes during a physical examination, but the definite diagnosis is
confirmed by surgery, usually laparoscopy. |
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Treatment of endometriosis includes medication and surgery for both pain relief and
treatment of infertility if pregnancy is desired. |
(Author: Melissa Conrad Stoppler; Editor: William C. Shiel, Jr.)
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