What Happens When Fetal Heart Abnormalities are Detected During an Ultrasound?

When pregnant patients and their families receive a prenatal diagnosis of a congenital heart defect (CHD), they often have a lot of questions and concerns about what comes next.

Lurie Children’s Fetal Cardiology & Neonatal Program, part of the nationally ranked Pediatric Heart Center and The Chicago Institute of Fetal Health, ensure families receive the most accurate diagnosis and the best counseling and treatment available.

Learn more below, where Fetal & Neonatal Cardiology Program Director Dr. Sheetal Patel answers some common questions about receiving a congenital heart disease diagnosis during pregnancy.

How is congenital heart disease diagnosed in utero?

A fetal echocardiogram is an ultrasound that we do through the pregnant patient's belly, similarly to what an obstetrician will do. But we are specifically looking at the baby's heart structure, heart function and the blood flow. We can detect if there are structural heart problems or if the heart is not working well. Fetal echocardiography mainly will give us all the information regarding baby's heart that we need to make an accurate diagnosis and a treatment plan.

We will also want to know if the fetus has other abnormalities such as kidney, brain, or lung conditions that will interfere with the management of heart condition. We sometimes utilize other testing, such as fetal MRI that shows if there are other organ abnormalities that we need to treat.

Unfortunately, not every congenital heart defect gets detected before birth. Barriers for the prenatal detection of CHD usually revolve around pregnant people not getting adequate prenatal care. Also, in some cases, prenatal images are so difficult to evaluate that the obstetrician never recognized that there was something wrong with the baby's heart, and therefore the referral to pediatric or fetal cardiology center was never made. 

What are some causes of a congenital heart condition in utero? Is it preventable?

We do not know the exact reasons CHD occurs. We can sometime figure out if there is a genetic abnormality in the fetus that is known to be associated with CHD. Sometimes these genetic abnormalities run in the family, but in so many cases, the causes of congenital heart disease will never be known.

Most CHD conditions are considered multifactorial, meaning that a lot of little things affect babies and their heart development.

CHD may be present along with other genetic conditions. For example, if the fetus has Down syndrome or Trisomy 21, then with those fetuses, about half of them would have a CHD. But the fact is, most of the congenital heart diseases are not associated with previously known risk factors that we could have predicted.

It is important for pregnant patients and families to hear that loud and clear: that it is not their fault, and they could not have prevented a congenital heart defect.

When is a heart condition typically diagnosed in utero?

CHD can be diagnosed any time after the first trimester of pregnancy, or even after birth, but our average referral gestational age is between and 18 and 22 weeks. When mothers get a level two (or more detailed) ultrasound, which is typically around 20 weeks gestation, and their obstetrician and is looking at baby's structure, they can often detect if something is not right about baby's heart. Obstetrical ultrasound only obtains limited images of the fetal heart. If an abnormality is suspected, a detailed fetal echocardiogram is indicated to accurately diagnose type and severity of CHD. The referral is made for fetal echocardiography, and that's how we get patients referred to us at Lurie Children’s for further evaluation and care.

Still, we can do evaluations earlier in pregnancy when needed. Fetal echocardiography can occur as early as 14 to 15 weeks of gestation. There are some limitations to early pregnancy fetal echocardiography because the heart is small, and it is difficult to see all the details but major cardiac abnormalities such as missing valve and missing chambers are easier to detect even with the early pregnancy fetal echocardiography.

What are some common heart defects diagnosed in utero? How common are they?

One out of 110 children will be born with congenital heart defect. Heart conditions or heart defects are the most common organ anomalies.

The most common CHD that we see is what’s called a ventricular septal defect (VSD), or a hole between lower two chambers of the heart.

More complex congenital heart defects include Tetralogy of Fallot, which is a combination of four different heart conditions, including a VSD and narrowing of the valve and blood vessel leading to the lungs. It causes a baby to have low oxygen saturation after they are born.

Cardiac surgery and regular follow-up with a cardiologist will be necessary to repair this condition.

There are other more not-so-common conditions that are more complex and require a lot of care and coordination. One is called Transposition of the Great Arteries (d-TGA), which can lead to low oxygen saturation as soon as a baby is born. Most babies with d-TGA need cardiac catheterization right after born, and surgery at a few days of age.

Another complex condition involves underdeveloped ventricles. They can be underdeveloped on the left side of the heart, a condition called hypoplastic left heart syndrome, or on the right side of the heart, which is hypoplastic right heart syndrome. These babies need immediate intervention after birth and then subsequent surgeries for the heart to work.

What can parents/guardians expect after delivery if a fetus is diagnosed with CHD?

Once there is a prenatal diagnosis of any congenital heart disease, whether it's a structural defect, arrhythmia or dysfunction of the heart, the pregnant patient will likely meet with specialists at least once a month.

In some cases, the location of where pregnant patients originally planned to deliver will change because some of the complex congenital heart defect diagnoses may require immediate cardiac intervention upon birth. Many times, complex congenital heart defect diagnoses lead to a recommendation to deliver at a tertiary care center where the specialists and resources are available to care for the baby with CHD. The delivery planning is also modified based on what they may need following birth, so sometimes labor would be induced so we can predict when the baby will be born and have a team of experts ready.

And then after the birth, we at Lurie Children’s have developed a streamlined process for transferring babies from their delivery room to the Regenstein Cardiac Unit, when needed.

When the baby arrives to the cardiac unit, we have all the medication, equipment and medical team members ready to meet their needs.

In most cases, we make this plan well before a baby’s arrival, ensuring their safety and wellbeing and the best possible outcome.

The last few decades have brought tremendous improvement in how we can provide comprehensive, wholesome care to these families who receive a CHD diagnosis in pregnancy. I look forward to even more advances and improvements in this type of care in the future.

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