Getting Tested for Cystic Fibrosis During Pregnancy

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Your obstetrician may have discussed having genetic testing done. This testing checks to see if either you or your spouse carry any genetic diseases. One disease that you will probably be tested for is cystic fibrosis.

What Is Cystic Fibrosis?

Cystic fibrosis is an inherited condition that primarily affects the lungs, but also affects the liver, pancreas, and intestines, and the sweat glands in the skin. It causes problems in the cells that produce mucus, sweat, and the enzymes in the intestines that digest food. About 30,000 people in the United States have cystic fibrosis.

Mucus sounds disgusting but it serves an important purpose in the lungs, the nose, and sinuses, and elsewhere in the body. Normally, mucus is a thin and slippery substance that helps lubricate the lungs and sinuses and helps keep them clean. In people with cystic fibrosis, however, because of a gene mutation, the mucus they produce is thick and sticky. It clogs the airways and traps germs that lead to lung infections. In the pancreas, the thickened mucus prevents the release of enzymes that help with digestion.

People with cystic fibrosis may develop lung infections frequently, be short of breath often, and have digestive problems like frequent diarrhea, foul-smelling greasy stool, or bad constipation. They also have very salty sweat. Because of the digestive problems and poor lung function, many people with cystic fibrosis are underweight and their physical growth may be impaired.

Men with cystic fibrosis may be infertile.

Not everyone with cystic fibrosis has the same severity of symptoms. Some people may have mild problems and may go undiagnosed for years, while others have more serious health issues that are seen soon after birth. There are more than 1,700 versions of a gene called the CFTR (cystic fibrosis transmembrane conductance regulator) gene and the severity of the disease depends on which defective version was inherited. CFTR changes a protein that regulates how salt moves in and out of the cells of the body. Symptoms of cystic fibrosis may also worsen over time.

Who Gets Cystic Fibrosis?

Cystic fibrosis is caused by a defective CFTR gene that a person must inherit from both of their parents. A person has to inherit two bad CFTR genes to have the disease.

More than 10 million Americans—about one in every 35 people–are what is known as carriers of cystic fibrosis. This means they have only one copy of the defective CFTR gene. They don’t have any symptoms of cystic fibrosis and may never know they carry the gene. The disease only occurs in people who inherit two copies, one from their mother and one from their father.

Cystic fibrosis is more common in white people than in people of other races, but it can occur in people of color. If you have someone in your family who has cystic fibrosis or is known to be a carrier, your chances of being a carrier are increased.

How Cystic Fibrosis Is Diagnosed

There are several steps to diagnosing cystic fibrosis. In the United States, all newborns are screened for several health conditions, including cystic fibrosis. Tests for the disease include a sweat test, and then genetic tests and a clinical evaluation at a center that specializes in cystic fibrosis.

Because of newborn screening, most people with cystic fibrosis are diagnosed very early.


There is no cure for the cystic fibrosis, but there are treatments that can help people with it live longer, healthier lives. Early treatment allows people to avoid serious lung infections that can damage the lungs and also helps prevent poor growth due to poor digestion.

Treatment can include bronchodilator drugs that help keep the airways open and mucus thinners that make it easier to clear mucus from the lungs. There are also drugs that help improve the function of the bad CFTR gene, which helps improve the lungs and digestion.

One treatment for this condition is airway clearance. These are techniques that include special breathing exercises and ways to cough so that mucus is expelled from the lungs rather than building up. There are also devices that use vibrations to loosen lung mucus and physical therapy that helps improve breathing.

At one time, children born with cystic fibrosis rarely lived to adulthood. Because of early diagnosis and better treatment, they now live well into adulthood and can lead happy lives.

Genetic Testing

The American College of Obstetricians and Gynecologists suggests that all couples who are considering having children have a genetic test for cystic fibrosis to find out if they are carriers. However, genetic testing is a personal decision.

Valerie DeBenedette
Valerie DeBenedette is an experienced health and medical writer who lives about an hour north of New York City with a dog that is smaller than her cat. Her work has appeared in magazines, newspapers, newsletters, and on websites. She is a member of the National Association of Science Writers.

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