People with cystic fibrosis (CF) can have children. While CF can interfere with fertility and increase the chance of certain pregnancy complications, it is possible for a person with CF to have a healthy pregnancy.

Cystic fibrosis (CF) is an inherited condition that causes the body to produce thick, sticky mucus.

CF occurs due to mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene.

The CFTR gene creates an important protein that controls the movement of sodium and water in the body’s cells.

Gene mutations impair the function of this protein, resulting in less water in a person’s mucus. This makes it sticky and thick and leads to internal blockages.

This article discusses CF and fertility, pregnancy, possible complications, CF heredity, treatments during pregnancy, and frequently asked questions.

A note about sex and gender

Sex and gender exist on spectrums. This article will use the terms “male,” “female,” or both to refer to sex assigned at birth. Click here to learn more.

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CF can cause fertility challenges in females for several reasons. These include:

Depending on the severity of the underlying CF, females with CF can become pregnant and have a healthy pregnancy, although it may take longer to conceive.

Most adult males with CF have functioning sperm in their testicles, but medical professionals consider them infertile.

In males, CF interferes with the development of the vas deferens — the tube connecting the testicles to the urethra, through which sperm exits the body.

This damage begins before they are born. While they are still in utero, retained secretions damage the vas deferens, resulting in congenital bilateral absence of vas deferens (CBAVD). This leads to an absence of sperm in their ejaculate.

Even though medical professionals consider males with CF infertile due to CBAVD, they still produce sperm. With the help of assisted conception in the form of sperm harvesting, they may be able to have biological children.

Some males with CF also live with hypogonadism, or testosterone deficiency, which can result in a low sperm count.

Assisted reproductive technology (ART) can help people with CF have biological children.

ART options include:

  • In vitro fertilization (IVF): Healthcare professionals harvest sperm and eggs and combine them in a laboratory to create embryos, which they transfer to the female’s uterus.
  • Intrauterine insemination (IUI): A catheter deposits sperm inside a female’s uterus, where it fertilizes an egg.

People with CF who want to try IVF may discuss the treatment implications with their healthcare team.

For people with CF, achieving and maintaining a healthy pregnancy requires some prior planning, risk management, genetic investigations, and treatment considerations.

Significant considerations include:

  • overall health
  • nutritional status
  • weight maintenance
  • lung function
  • safety of CF medications for pregnancy

People with CF hoping to become pregnant may benefit from a dietitian’s support to plan for increased caloric intake, sufficient hydration, and vitamin supplementation.

The Cystic Fibrosis Foundation (CFF) recommends that a person with CF have a forced expiratory volume (FEV1) of at least 50% before becoming pregnant. FEV1 is a measure of how much air a person can exhale in 1 second.

According to the CFF, most pregnancies involving a pregnant parent with CF carry to full term, and there is no clear increase in the chance of birth defects.

However, according to a 2023 paper, some data suggest that people with CF are more likely to have preterm births.

However, pregnant people with CF have a higher chance of some complications, including:

Preterm delivery may be more likely to occur if the pregnant parent has diabetes or experienced low lung function before pregnancy.

Whether a pregnant person with CF passes the condition to their child depends on the status of the other biological parent.

If the nonpregnant biological parent also has CF or is a CF carrier, there is a chance the infant may have CF as well.

If both parents carry a recessive gene for a disorder such as CF, there is a 25% chance that the child will inherit the gene from each parent and develop the disorder. There is a 50% chance that the child will also be a CF carrier, like the parents.

If only one parent is a carrier, there is a 50% chance that the child will be a CF carrier.

Prenatal diagnostic testing can help determine whether an unborn child has CF or is a CF carrier.

There are two types of tests that parents can request:

  • Amniocentesis: Between the 15th and 20th weeks of pregnancy, doctors use a fine needle to remove a small amount of amniotic fluid to test for the presence of the CF gene.
  • Chorionic villus sampling (CVS): Doctors extract a small sample of placental tissue between the 10th and 13th weeks of pregnancy to test for the CF gene.

Prospective parents using in vitro fertilization can request preimplantation testing.

This process tests embryos for CF and other genetic disorders before healthcare professionals transfer the embryo to the female’s uterus.

Yes, a person with CF can safely chest or breastfeed.

However, chest or breastfeeding can tire out the person and use up many calories, which can affect the health of a person with CF.

A person should discuss their options with a healthcare professional to help them decide whether breast or chestfeeding is the right decision for them and their child.

Most medications for treating CF are safe to take during pregnancy and chest or breastfeeding.

However, there is limited safety information about CFTR modulator medications. This is partially because pregnancy is often an exclusion criterion for clinical trials.

During pregnancy, a person with CF should consider several factors when making treatment decisions. These include:

  • benefits to the pregnant parent
  • possible harm to the fetus
  • risks of stopping treatment

Frequent and regular prenatal checkups can allow for regular monitoring of important health markers such as lung function and oxygen saturation.

CF treatments considered safe to continue during pregnancy include:

  • pancreatic enzyme replacement therapy (PERT)
  • vitamin supplementation
  • inhaled mucolytics hypertonic saline and dornase alfa
  • airway clearance therapy (ACT)
  • physiotherapy
  • inhaled antibiotics, if needed

The recommended vitamin A intake during pregnancy is around 800 µg (micrograms) per day, but no more than 10,000 IU (international units) daily, as higher doses early in pregnancy may harm the fetus.

It is also best to monitor the pregnant person’s nighttime blood oxygen level.

Certain antibiotics doctors use to treat CF infections and lung exacerbations may pose some risk to the unborn child.

Pregnant people with CF can discuss the risk versus benefit profile for each medication as it applies to their situation.

People with CF can have children. Some females with CF can conceive naturally, but females with CF have higher rates of subfertility and infertility. Having CF may increase the time it takes for a person to conceive.

Males with CF will need fertility treatments to help their partner conceive. This is due to abnormalities in the vas deferens that cause their ejaculate not to contain sperm.

The chance of the child being born with CF or as a CF carrier depends on the genetic status of both parents.

Having CF while pregnant may increase the chance of some complications, such as preterm delivery.

However, it is possible for a person to have healthy, full-term pregnancies by following the recommendations of a healthcare team.