By Colette Bouchez
HealthScoutNews Reporter

TUESDAY, March 5 (HealthScoutNews) -- Looking at your family tree just might give you an important clue about your fertility.

New research shows the incidence of the fertility-robbing menstrual disorder known as endometriosis may have far deeper genetic roots than previously thought.

In studies presented in the March issue of Human Reproduction, a group of Icelandic researchers found that having a sister or mother who had endometriosis increases your risk by fivefold. In addition, even having a second, third or fourth cousin with this disorder means your risk is greater than 50 percent, the researchers say.

"We have always known that endometriosis had a genetic component, but we were not aware that it was as extensive as this study has found," says Dr. Ernst Bartsich, associate clinical professor of obstetrics and gynecology at Weill Cornell Medical Center in New York City.

Endometriosis is thought to affect up to 5 percent of all women in their reproductive years. It develops when small bits of uterine lining meant to slough off and leave the body during a menstrual period instead flow back into the reproductive system.

Landing almost anywhere within the pelvis, including the fallopian tubes and ovaries, the tiny bits of misplaced tissue attach and begin growing. Then, each month the hormonal stimulation of a new menstrual cycle encourages the misplaced tissue to grow as well.

Depending on where in the reproductive system the misplaced tissue is growing, a number of fertility problems can occur, Bartsich says.

Endometriosis can cause a number of symptoms in many women that are hard to miss, including severe menstrual pain, or pelvic or back pain. However, for some women, the disease can be silent, at least in its early stages. These women won't have a clue their fertility may be in jeopardy.

"Many women discover they have endometriosis only after they try to get pregnant and find that they can't," says Dr. Nabil Husami, director of the Endometriosis Center at Sloane Hospital for Women at Columbia Presbyterian Medical Center in New York City.

Husami says the new study is important because it may encourage a woman to question her family members about any incidence of endometriosis, and help her learn more about her own potential to get pregnant.

"If your sisters have endometriosis, if your cousins have it, then you may have it as well, in which case the sooner you have your children, the easier it will likely be for you to get pregnant," Husami says.

The reason for the urgency, Husami says: The longer you have endometriosis, the more likely it is to compromise your fertility.

The new study involved the entire country of Iceland, and was the first to analyze the occurrence of endometriosis across a total population. Conducted by scientists from a genetic research company named deCODE, the study relied on a computerized genealogical database that supplied information on some 290,000 current residents of Iceland. It was also able to track up to 85 percent of those who ever lived in Iceland, going back as far as the ninth century.

Working with the department of Obstetrics and Gynecology at the National University Hospital in Iceland, the genetic researchers compiled a list of 750 Icelandic women who had a surgical diagnosis of endometriosis (the only sure way to know the disease is present) between 1981 and 1993.

The list was then entered into the computer, where it was compared against the giant genealogical database that analyzed the women's family connections.

Then the researchers entered the names of 750 women who did not have endometriosis, and applied the same analysis process.

The scientists were able to show the women with endometriosis were far more inter-related than the randomly selected members of the control group.

Moreover, they learned that if a first-degree relative -- such as a sister -- had endometriosis, a woman was up to five times more likely to have the disease. If a second, third or fourth cousin had it, the woman was at least 50 percent more likely to develop endometriosis.

The researchers hope their data will lead to the development of a simple DNA-based blood test to diagnose endometriosis without surgery and tell a woman if she's at risk long before symptoms or problems appear.

"Although there are no current treatments to prevent endometriosis, certainly knowing you are at risk, or even that the disease has already started, would be extremely helpful when planning your family. If you had a choice, you probably would not want to postpone childbearing any longer than was necessary," Bartsich says.

Knowing there could be a problem getting pregnant, he adds, would hopefully encourage a woman to seek help sooner rather than later if, in fact, she tries to conceive and finds she's unable to do so.

What To Do: For more about endometriosis, visit The Endometriosis Association or The Endometriosis Research Center. To learn how endometriosis can interfere with your fertility, visit About.com.

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