During a normal menstrual cycle, the lining of your uterus -- called the endometrium -- begins to thicken in preparation for becoming pregnant. If you don't become pregnant that month, your body sheds the endometrium during menstruation and the process starts over. In endometriosis, for reasons that doctors don't entirely understand, tissue very similar to the endometrium begins to grow outside the uterus in various places that it shouldn't. It can appear in or on the ovaries, the fallopian tubes, the various structures that support the uterus, and the lining of the pelvic cavity. Sometimes, it's found in other places as well, including the cervix, vagina, rectum, bladder, bowel, and elsewhere.
There is no way to prevent endometriosis. But there are several things that raise your risk of developing it:
Having a close relative with endometriosis, especially a mother or a sister
Having a short menstrual cycle -- less than 25 days
Having menstrual flow lasting more than a week
Having heavy flow
Having medical condition that blocks or constricts your cervix or vagina
Having a birth defect of the uterus, such as a double uterus or a double cervix
The problem is that this tissue behaves like normal endometrial tissue -- it builds up and breaks down with your menstrual cycle -- but it can't be shed like normal endometrial tissue during your period. As a result, endometriosis can cause irritation, inflammation, and the formation of scar tissue. This buildup of tissue can prevent the eggs from getting out of the ovaries or being fertilized by sperm. It can also scar and block the fallopian tubes, preventing the egg and sperm from meeting.
Some women with endometriosis do not have symptoms.
Getting Pregnant When You Have Endometriosis
Most women who have endometriosis can conceive normally. But if you're having problems getting pregnant, endometriosis may be the cause. To find out, your doctor may suggest a laparoscopy. In this procedure, a surgeon inserts a small camera through a tube into your abdomen to check for abnormal endometrial tissue. The surgeon might want to confirm the diagnosis with a biopsy. If you've been diagnosed with endometriosis, you have several treatment options, depending on the severity of the disease.