Endometriosis is when the tissue that makes up the uterine lining (the lining of the womb) is present on other organs inside your body. Endometriosis is usually found in the lower abdomen, or pelvis, but can appear anywhere in the body. Women with endometriosis often have lower abdominal pain, pain with periods, or pain with sexual intercourse, and may report having a hard time getting pregnant. On the other hand, some women with endometriosis may not have any symptoms at all.
Endometriosis is estimated to affect between 3% and 10% of reproductive-aged women. Endometriosis can only be truly diagnosed by a doctor performing a laparoscopy (a surgery where a doctor looks in the abdomen with a camera usually through the belly button) and taking a sample of a suspected abnormality. Thus, the proportion of women affected by endometriosis differs among women having surgery for different reasons. In women without symptoms who are having surgery for elective sterilization (having their tubes tied), 1-7% will actually have endometriosis diagnosed at the time of their surgery, as will 12-32% of women having surgery for pelvic pain, and 9-50% of women having surgery for infertility. Endometriosis is rarely found in girls before they start their period, but it is found in up to half of young girls and teens with pelvic pain and painful periods
There are several different ideas of how and why endometriosis happens. One idea is that when a woman has her period, some of the blood and tissue from her uterus travels out through the fallopian tubes and into the abdominal cavity. This is called retrograde menstruation. Another idea is that some cells in the body outside of the uterus can change to become the same kind of cells that line the uterus. This is a common explanation for endometriosis at unusual sites like the thumb or knee. Another possible explanation is that the cells from the lining of the uterus travel through the blood vessels or through the lymphatic system to reach other organs or body areas. Also, endometriosis can spread at the time of surgery. For example, a woman with endometriosis that undergoes a cesarean section could inadvertently have some endometriosis cells attach to the abdominal incision so that she has endometriosis in the scar from the surgery Interestingly, nearly all women have some degree of retrograde menstruation, but only a few women will get endometriosis. This may be due to differences in a woman’s immune system. Also, endometriosis is much more common if a close relative also has endometriosis, so there may be genes that influence endometriosis.
When a woman with endometriosis has her period, she has bleeding not only from the cells and tissue inside the uterus, but can also have bleeding from the cells and tissue outside the uterus. When blood touches these other organs, especially inside the abdomen, it can cause inflammation and irritation, creating pain. Sometimes, scar tissue can also develop from the endometriosis which can also contribute to the pain.
Endometriosis and Fertility Between 20 and 40% of women with infertility will have endometriosis Endometriosis seems to impair fertility in 2 ways: first, by causing distortion of the fallopian tubes so that they are unable to pick up the egg after ovulation, and second, by creating inflammation that can adversely affect the function of the ovary, egg, fallopian tubes or uterus
Pain, including pelvic or lower abdominal pain and pain with menses, is the most common symptom of endometriosis. Women may also have pain with intercourse. The symptoms are often “cyclical” meaning that the pain is worse right before or during the period, and then improves. Women may have constant pelvic or lower abdominal pain as well. Other symptoms include subfertility, bowel and bladder symptoms (such as pain with bowel movements, bloating, constipation, blood in the urine, or pain with urination), and possibly abnormal vaginal bleeding.
To diagnose endometriosis, a doctor must perform a laparoscopy (a surgery where a doctor looks in the abdomen with a camera usually through the belly button) and take a sample of a suspected endometriosis lesion Some physicians and patients may try to treat suspected endometriosis with certain medications to see if symptoms are improved without having to undergo surgery. Although this may be possible, endometriosis cannot be diagnosed by improvement in symptoms with medication alone. During surgery, endometriosis lesions are often described as looking like “cigarette burns” inside the abdomen, although there are many different variations as to how an endometriosis lesion may appear. Endometriosis can be located on and even within an ovary, causing an endometrioma, or a cyst of endometriosis. These cysts are often referred to as “chocolate cysts,” because the material inside the cyst looks like chocolate syrup.