Cystic fibrosis and pregnancy

Cystic fibrosis (CF) is a condition that affects breathing and digestion. It’s caused by very thick mucus that builds up in the body.

Mucus is a fluid that normally coats and protects parts of the body. It’s usually slippery and slightly thicker than water. But In CF, the mucus is thicker and sticky. It builds up in the lungs and digestive system and can cause problems with how you breathe and digest food.

What causes CF?

CF is inherited. This means it’s passed from parent to child through genes. A gene is a part of your body’s cells that stores instructions for the way your body grows and works. Genes come in pairs — you get one of each pair from each parent.

Sometimes the instructions in genes change. This is called a gene change or a mutation. Parents can pass gene changes to their children. Sometimes a gene change can cause a gene to not work correctly. Sometimes it can cause birth defects or other health conditions. A birth defect is a health condition that is present in a baby at birth.

You have to inherit a gene change for CF from both parents to have CF. If you inherit the gene change from just one parent, you have the gene change for CF, but you don’t have the condition. When this happens, you’re called a CF carrier. A CF carrier has the gene but doesn’t have the condition.

If you and your partner both carry the gene change for CF, your baby may get two CF gene changes (one from each of you) and have CF.

Can you pass CF to your children?

Yes. But it depends on both you and your partner. If you and your partner both have CF, your baby will have CF.

If you and your partner are both CF carriers, there is a:

  • 3-in-4 chance (75 percent) that your baby won’t have CF
  • 1-in-2 chance (50 percent) that your child won’t have CF but will be a CF carrier
  • 1-in-4 chance (25 percent) that your child will have CF
  • 1-in-4 chance (25 percent) that your child will not have CF and not be a carrier

A genetic counselor can help you understand your chances of passing CF to your baby. A genetic counselor is a person who is trained to help you understand about how genes, birth defects and other medical conditions run in families, and how they can affect your health and your baby's health.

Ask your health care provider if you need help finding a genetic counselor. Or contact the National Society of Genetic Counselors.

How can you find out if you’re a CF carrier?

There are two types of tests that can tell you if you have CF or if you’re a carrier. Both are safe to take during pregnancy. Your partner can have the tests, too.

  • A blood test
  • A swab of cells inside your mouth. This means your provider rubs a cotton swab against the inside of your cheek to get some cells.

Your provider sends the blood or swab sample to a lab for testing.

The American College of Obstetricians and Gynecologists (ACOG) recommends that health care providers make CF carrier screening available to all couples. It’s often done as a routine prenatal test in early pregnancy.

About 1 of 31 people in the United States is a CF carrier. You and your partner may want to have CF carrier testing if:

  • CF runs in either of your families. You also may want to get genetic counseling. Genetic counseling can help you understand your chances of having a baby with CF and what kind of treatment he may need if he does.
  • You are:
    • Caucasian and your family comes from Northern Europe. About 1 of every 25 people with this ancestry is a CF carrier.
    • Hispanic. One out of every 62 Hispanics in the United States is a CF carrier.
    • African-American. One out of every 65 African-Americans in the United States is a CF carrier.
    • Asian American. One out of every 94 Asian Americans in the United States is a CF carrier.

Can you find out during pregnancy if your baby has CF or is a CF carrier?

Yes. If you or your partner has CF or is a CF carrier, you can have a prenatal test to find out if your baby has the condition or is a carrier.

You can have either of these tests:

  • Chorionic villus sampling (also called CVS). This test checks tissue from the placenta for birth defects and genetic conditions. You can get CVS at 10 to 13 weeks of pregnancy.
  • Amniocentesis (also called amnio). This test checks amniotic fluid from the amniotic sac around your baby for birth defects and genetic conditions. You can get this test at 15 to 20 weeks of pregnancy.

Talk to your provider or genetic counselor if you’re thinking of having either of these tests.

Can CF cause problems with pregnancy?

Some women with CF may have trouble getting pregnant, but many can get pregnant and have a healthy pregnancy. Some men with a mutation in the same gene that is responsible for CF may be infertile. This means they can’t get their partner pregnant. They may or may not have CF symptoms. If you and your partner are having trouble getting pregnant, ask your provider or genetic counselor about this.

Women with CF may have a higher risk of getting gestational diabetes. Diabetes is when you have too much sugar in your blood. Too much sugar in your blood can damage organs in your body, including blood vessels, nerves, eyes and kidneys. Diabetes must be treated during pregnancy for the health of the mother and the baby, and after pregnancy for the health of the mother.

How is CF treated in pregnancy?

If you have CF and are thinking about getting pregnant, talk to your provider. You need ongoing care throughout pregnancy from your provider and other specialists experienced with CF.

More information

See also: Genetic counseling, Newborn screening, Your family health history

Last reviewed: January, 2013