Do doctors know what causes endometriosis and if it can be prevented?

Endometriosis is a condition in which the same type of tissue that lines the uterine cavity (endometrium) is found outside the uterus in places it does not belong. This condition, which affects roughly 10 percent of women, can cause painful menstrual periods, pain with intercourse, pain with bowel movements, low back pain, infertility, and menstrual irregularities. Typically, the tissue transplants on the fallopian tubes, the ovaries, the bladder, and on the surface of the bowels. But tissue may also be found in remote areas like the lungs, and has even been described in men who have received estrogen!

It's not fully understood why the condition occurs, but genetics may play a role. We know, for example, that if you have a first-degree relative (mother, sister, daughter) with endometriosis, then your chance of having it is increased five- to sevenfold. The most accepted theory for how endometriosis happens is "retrograde menstruation," which suggests that during a period, some of the uterine lining that is shed backs up through the fallopian tubes and is deposited outside the uterus. Still, some women who have retrograde menstruation don't develop endometriosis. And this theory doesn't explain why women who have had their tubes tied can still get endometriosis or how endometrial tissue ends up in places like the lungs.

Some researchers believe blood and lymph vessels may play a role in the transport of endometrial fragments. Another theory suggests that a certain type of cell is somehow transformed into endometrial tissue. Obviously, we don't have all the answers yet.

Without knowing how or why endometriosis develops, it's not likely that it can be prevented. Still, if you're concerned, it may be a good idea to avoid douching, especially during a menstrual period. You don't want the pressure of the douche to potentially force any uterine lining tissue back through the fallopian tubes. Your best bets for dealing with endometriosis are to recognize the symptoms early and seek appropriate treatment from your doctor.