Cystic Fibrosis Prenatal Screening and Diagnosis
What is cystic fibrosis?
Cystic fibrosis (CF) is a type of genetic disorder. Thick mucus gathers in your lungs and intestines, and causes permanent damage. It causes problems with breathing and digestion. CF is a disorder that gets worse over time. People who have CF have a shorter life expectancy.
A baby can be born with CF when both parents pass on the CF gene. This can mean one or both parents have CF, or they carry the gene. Children have a 25% chance of having CF if both parents have the gene.
What is prenatal screening?
Prenatal screening is a test that your doctor performs while you are pregnant. It is done to check for any health problems with your baby before they are born. Problems include genetic disorders that run in families, such as CF. Other examples are birth defects, neural tube defects, and HIV.
Path to improved health
At your first prenatal visit, the doctor will talk to you about screening and tests. Although they may offer suggestions, it is your choice if you want to do the screenings or not.
If you don’t know if you have or carry CF, you will need to do carrier screening first. This is a simple test that checks to see if you or your partner carries the CF gene. The doctor will collect a blood, saliva, or tissue sample from inside your cheek. Typically, carrier screening is done one person at a time. It can be done before or during pregnancy. The possible results are:
- You (or your partner) test negative for CF. The other person does not need to be tested.
- You (or your partner) test positive for CF. The other person should be tested.
- You and your partner both test positive for CF. If you are pregnant, you should consider the prenatal testing to see if your baby has CF. If you are not pregnant but are trying, talk to the doctor about your options. You may consider adopting or using fertility treatment to avoid the CF gene.
Screening for CF in a baby can be done one of two ways.
- Chorionic villus sampling (CVS). The doctor collects a sample of tissue from your placenta. This test is done between 10 and 13 weeks of pregnancy.
- Amniocentesis. The doctor collects a sample from your amniotic fluid. This test is done between 15 and 20 weeks of pregnancy.
If the prenatal screening is positive for CF, you have two options.
- You can continue with your pregnancy. The diagnosis does not affect ongoing prenatal care. In the remaining months, do research to learn more about CF. Talk to your doctor about treatment options. You may consider joining a support group.
- You can end your pregnancy. This decision consists of legal and moral considerations.
Things to consider
Although screening can be helpful, it also can create added worry or concern. If you choose not to screen during pregnancy, most states check for CF during newborn screening. This is a series of tests your baby undergoes in the hospital after birth. These include blood, hearing, and heart tests. Talk to your doctor to see what your state’s testing includes.
Keep in mind that no screening is 100% effective. Carrier and prenatal screenings cannot check for all gene mutations. If the tests are negative, there still is a rare chance you carry CF or your baby could have CF.
When to see your doctor
Talk to your doctor if:
- you and your partner both have CF
- you and your partner are known carriers for CF
- you and your partner have a family history of CF
- you and your partner are pregnant or trying to become pregnant and want to learn more about genetic testing.
Questions to ask your doctor
- What are the risks and benefits of CF prenatal screening?
- Does my state test for CF during the newborn baby screening?
- If my partner or I test negative in the carrier screening, what is the chance our baby could still have CF?
- If we have a child with CF, what are the chances our other children will have CF?
- Are there other prenatal screening tests that I should consider?