Congenital heart disease

What is Congenital Heart Disease?

Congenital heart disease occurs in about 8/1000 pregnancies. There is a wide range of congenital heart defects, from minor anomalies that do not need any treatment to severe defects that are incompatible with life. The exact cause is unknown for most kinds of heart disease. We do however know that some women are predisposed to have a baby with heart disease. This includes women who have a heart defect themselves, women who take specific types of medication or who have certain medical conditions, such as diabetes or lupus. Women who have had a previous child with a heart defect are also at slightly higher risk of having another pregnancy complicated by a fetal heart defect. Some kinds of congenital heart disease are associated with genetic or syndromal anomalies.

Most congenital heart defects can be diagnosed by ultrasound at 18-22 weeks gestation. Some heart defects however may only be diagnosed at or after birth. Sometimes an ultrasound done in the first trimester of pregnancy may already show some indirect markers (clues) of fetal heart disease, such as an increased nuchal translucency or abnormal blood flow in some fetal vessels.

In fetuses at high risk for congenital heart disease, a specialized ultrasound of the fetal heart (echocardiogram) is indicated. This is done by a paediatric cardiologist (doctor specialized in heart anomalies in children) in a specialized center such as the Sick Kids Hospital, Toronto. 

What is the outcome for a fetus with Congenital Heart Disease?

The outcome for a fetus with congenital heart disease varies widely depending on the exact nature of the heart defect. Some minor anomalies may not need any treatment and resolve naturally. These conditions are associated with excellent long-term outcomes. More severe forms of heart disease may not be compatible with life or may require major open-heart surgery after birth. A paediatric cardiologist will be able to determine the nature of the heart disease in your fetus and will counsel you in detail about the expected outcomes and the required treatments. 

What other tests should we consider?

Every fetus with suspected congenital heart disease should have a detailed fetal echocardiogram in a specialized center. These fetuses also need to have a detailed ultrasound in specialized perinatal center, such as the Fetal Medicine Unit at Mount Sinai Hospital, to look at the other fetal organs and rule out associated anomalies. Certain types of heart disease are more commonly associated with chromosomal problems. You may therefore be offered an amniocentesis  to determine the fetal karyotype and rule out othe genetic conditions.

What therapy is available?

Therapy for an infant or fetus with congenital heart disease depends on the exact nature of the problem. In some cases, no therapy will be required. These babies can then be born in a local hospital. In some cases, specialized care will be required immediately after birth. These babies may then need to be born in a specialized perinatal center such as Mount Sinai Hospital. For certain rare cardiac anomalies such as critical aortic stenosis (narrowing of the aorta), pulmonary stenosis with intact ventricular septum (narrowing of the blood vessel going towards the lungs) or hypoplastic left heart syndrome with intact atrial septum, interventions before birth may improve the outcomes after birth. These interventions are offered in the Fetal Medicine Unit at Mount Sinai Hospital in conjunction with cardiologists from Sick Kids Hospital, Toronto.

What is the long-term outcome for a fetus with Congenital Heart Disease?

This will depend on the actual heart defect.

Find out more about specific heart conditions at About Kids’ Health, Sick Kids Hospital (Toronto):

Special Pregnancy Program

Referrals »

Fetal Medicine: 416-586-4800 x 7756
Fax: 416-586-3216

Maternal Medicine: 416-586-4800 x 7000
Fax: 416-586-5109

Main clinic hours: Monday to Friday, 8am to 4pm

Prenatal Diagnosis & Medical Genetics

Referrals »

phone: 416-586-4800 x 4523
fax numbers:
416-586-4723 or 416-586-8384

Perinatal Mental Health

Referrals »

Phone: 416-586-4800 x 8325
Fax: 416-586-8596