A guide for families
A diagnosis before birth gives your family time to learn, ask questions, and make a care plan.
What the heart scan shows.
What the team will watch during pregnancy.
Where and how your baby will receive care.
Start with normal blood flow
The heart has four chambers. The two lower chambers, called ventricles, pump blood out.
Understanding the diagnosis
Tetralogy of Fallot (TOF) is a heart condition that develops before birth.
Before and after birth
During pregnancy, oxygen reaches your baby through the placenta and umbilical cord.
The lungs do not yet do the work of breathing. Many babies with TOF remain stable while the team follows their heart.
The lungs take over. A temporary blood vessel, the ductus arteriosus, begins to close. Some babies need help getting enough blood to their lungs.
When there is another finding
TOF does not always come with the same set of other heart differences.
The ventricular hole and narrowed lung pathway are central findings. A shared valve is not part of every TOF diagnosis.
An atrioventricular septal defect (AVSD) affects the center of the heart. A complete AVSD includes holes and a shared valve instead of two separate valves.
The next scan
A fetal echocardiogram, or “fetal echo,” is a special ultrasound of your baby’s heart.
Look carefully at chambers, valves, and blood vessels.
See how blood moves toward the lungs and body.
Discuss what is known and what still needs follow-up.
Genetics and your choices
Some babies with TOF have a chromosome or gene change. Many do not have an identified cause.
A blood screening test cannot rule out all genetic conditions linked with a heart difference.
Amniocentesis tests cells from the fluid around the baby. Chromosomal microarray looks for missing or extra pieces of DNA, including 22q11.2 deletion.
Following the pregnancy
Your team will set a schedule based on your baby’s heart and the rest of your pregnancy.
Check the pathway to the lungs, blood flow, and how well the heart is working.
Follow growth and other findings. Tell your team about new concerns and follow their advice on fetal movement.
Your birth plan
The right hospital is one that can provide the care your baby is expected to need.
Ask who will assess your baby, when the heart ultrasound will happen, and how a transfer would work if needed.
TOF alone does not automatically mean an early birth or cesarean. Your obstetric and heart teams will advise you.
The first hours
The team checks breathing, oxygen levels, and the heart’s anatomy.
Assess your baby and measure oxygen levels.
Perform a newborn heart ultrasound.
Provide monitoring, medicine, or an early procedure if needed.
Prostaglandin E1 is medicine that can keep the temporary ductus vessel open. Some babies need this to maintain blood flow to their lungs while the team plans treatment. It is not needed by every baby with TOF.
Planning treatment
The aim is to close the ventricular hole and improve the route to the lungs.
Some babies can grow before their planned repair. The surgeon explains the approach and timing for your child.
Other babies need support or a procedure soon after birth, followed by a later repair. A very narrow or closed lung pathway may change the plan.
Beyond the first repair
Many people with repaired TOF reach adulthood. Follow-up remains part of their care.
The team follows heart rhythm, valve function, and exercise needs. Some people need further procedures.
Discuss feeding, growth, development, and family support. Ask which resources are available near you.
Your next steps
Use this checklist in your conversation with your team.
Questions to ask your MFM specialist
Bring the questions that matter most to your family.
Trusted resources
Patient resources and the professional guidance behind this presentation.
Your family • your care team
A clear plan can make the next step feel more manageable.
This guide supports discussion with your clinicians. It cannot diagnose your baby or predict an individual outcome.
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