Tetralogy of Fallot found before birth: what it means and what happens next

Tetralogy of Fallot is a type of congenital heart disease, which means a heart condition a person is born with. The British Heart Foundation explains that it affects how the heart works and how blood flows through it, and that it is made up of four different problems.

These are pulmonary stenosis, a narrowing of the valve that lets blood flow from the heart to the lungs; right ventricular hypertrophy, where the right pumping chamber grows larger and the muscle thickens because it is working harder; a ventricular septal defect, a hole in the wall between the two main pumping chambers; and an over-riding aorta, where the aorta sits above the hole. Because of the hole and the position of the aorta, blood with little oxygen can be sent around the body, which can cause the skin and lips to turn blue or grey, known as cyanosis.

The British Heart Foundation says many people with tetralogy of Fallot live a normal life, but that over time it can cause other heart problems such as heart failure and high blood pressure, which is why long-term specialist follow-up matters.

The NHS says the 20-week screening scan, also called the anomaly scan, is an ultrasound scan to look for 11 different conditions in your baby, and that serious cardiac abnormalities are one of them. It is usually done when you are between 18 and 21 weeks pregnant, and the person doing the scan looks closely at the baby's bones, heart, brain, spinal cord, face, kidneys and tummy.

The NHS is clear about the limits of the test: some conditions can be seen more clearly than others, so the scan may not find everything, and the NHS congenital heart disease page says it is possible for congenital heart disease to be missed and sometimes not diagnosed until adulthood. If you have any symptoms or something does not feel right, the NHS says it is important to tell your midwife.

Not everyone chooses to have the scan, and the NHS says it is your choice. If you decided not to and change your mind, you can speak to your midwife or GP.

The NHS says that if the scan finds something you may be offered more scans and tests, such as amniocentesis or chorionic villus sampling, and you will be referred to a specialist who will explain the tests to help you decide whether you want them. These tests can tell you whether your baby definitely has a health condition and what that means for you and your baby.

For a suspected heart condition, specialist assessment may include a more detailed scan of the baby's heart. Your care team will talk through what has been seen, whether other conditions are involved, where the baby is best cared for around birth and what the options are. The NHS also names Antenatal Results and Choices (ARC) as a charity with information about screening tests and how you might feel if you are told your baby has, or might have, a condition.

It is normal to feel shocked and to need time. Ask for information in writing, take someone with you to appointments and ask who your main contact is.

The British Heart Foundation says surgery is the only way to treat tetralogy of Fallot and that it is usually done in childhood. Some babies first have a shunt operation, a temporary procedure that improves the blood flow to the lungs while waiting for complete repair, usually done within the first four to six months of life if it is needed.

Complete repair is open heart surgery, often done within the first few years of life. It usually includes sewing a patch over the hole in the heart and widening the narrowed pulmonary valve and artery, with part of the thickened tissue sometimes removed. The British Heart Foundation says people usually stay in hospital for a few weeks after complete repair and are prescribed medicines for a short time at home. The NHS notes that, depending on the heart condition, surgery may be needed as soon as a baby is born or much later in life.

The NHS says that with congenital heart disease you may be referred to a specialist team at an NHS hospital, and some babies have symptoms from birth, such as difficulty feeding, slow weight gain and swelling. It says to call 999 if a baby or child's lips, tongue, face or skin suddenly turn blue or grey, or if they have difficulty breathing.

After repair, most people with tetralogy of Fallot live a normal life, according to the British Heart Foundation. It says you will be offered appointments at a congenital heart disease specialist clinic to check your heart for the rest of your life, and that these are important even when you feel well because changes can occur before symptoms.

A common issue after repair is a leaky pulmonary valve (pulmonary regurgitation), which puts extra strain on the heart and can cause tiredness and breathlessness. Other possible issues the British Heart Foundation lists include abnormal heart rhythms, blood leakage through the hole, endocarditis and heart failure. It says people with congenital heart conditions have an increased risk of endocarditis, and that antibiotics may be recommended before some procedures. If the repair is good and there is no obstruction or leak, many people can exercise fully, and the cardiology team can advise on activity.

Pregnancy in someone with tetralogy of Fallot themselves needs specialist planning. The British Heart Foundation says to let your doctor know if you are pregnant or planning to be, because there may be more risk of problems.

In the UK, a suspected heart anomaly on a screening scan is generally referred to a fetal medicine or fetal cardiology service within the NHS, with surgery performed at specialist children's heart centres. Some families also seek a private fetal medicine opinion for a further scan or second opinion. Whichever route is used, a single named specialist team should coordinate scans, delivery planning and care after birth.