Articles and Topics
Cystic Fibrosis Screening
Technology keeps providing your obstetrician with new ways to help determine the health of your unborn baby. In recent years, a new screening test to detect a serious health condition, Cystic Fibrosis, has become available. Cystic Fibrosis is a genetic disease passed on when both parents carry a specific gene. Surprisingly, 1 in 29 Caucasians in North America carry the gene and 1 in 2,500 Caucasian children are affected.

Cystic Fibrosis is a serious condition caused by abnormally thick secretions in the lungs. These secretions cause difficulties with breathing, numerous infections and scarring of the lungs. Children with Cystic Fibrosis also have intestinal problems and an increased risk of developing diabetes. Typically, they have a shortened life expectancy of 31 years, although some individuals have survived into their 50's.

Although there are over 800 genetic abnormalities associated with Cystic Fibrosis, the vast majority of cases in the Caucasian population are caused by just 30 abnormal genes. Therefore, we can effectively screen them with a high degree of confidence through a simple blood test focusing on these 30 specific gene markers.

The American College of Obstetricians and Gynecologists recommend screening: Adults with a family history of Cystic Fibrosis;

Partners of individuals with Cystic Fibrosis;

Caucasian couples of European and Ashkenazi Jewish background who are pregnant or planning on getting pregnant. If you and/or your partner are from other ethnic groups, you have a much lower risk of having a child with Cystic Fibrosis. Although testing is also available to you, it tends to be less accurate because you are more likely to carry one of the less common genes. These genes are not tested on the routine Cystic Fibrosis test. You should speak with your health care provider about the merits of doing the testing.

When screening for Cystic Fibrosis, I begin by testing my patient. If her test is positive—meaning she is a carrier of the gene for the disease, not that she has the disease herself—I will ask her partner to undergo the same test. If they both carry the exact same gene, they have a 25% chance of having a child with Cystic Fibrosis. Yet they still have a 75% of having a perfectly normal child. For these individuals, genetic testing will be offered during the pregnancy to determine if their child is effected.

Some of my patients mistakenly believe that if they carry the gene for a Cystic Fibrosis, they will get sick with the disease. This is not correct.

Fifty percent of the time, a carrier of an abnormal gene for Cystic Fibrosis will pass that gene on to their children. Then those children will also be carriers, and should be informed of their potential risk before they have children. It is also a good idea for carriers to speak with their siblings to make sure they get the proper screening, as well.

Anytime I speak with my patients about testing, I know they are nervous. Sometimes they're fearful of getting an unfavorable test result, while other times they're thinking about a disturbing story somebody told them. As an obstetrician, I try to ease the strain and misconception surrounding a test by providing my patients with proper information and discussing the possible findings in advance. Your health care provider most certainly strives to do the same, so be sure to speak with him or her if you have any questions.
Craig L. Bissinger M.D.