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What Can Cause Congenital Heart Defects?

What Can Cause Congenital Heart Defects?

Congenital heart disease (CHD) is defined as an abnormal condition of the heart that is present at birth. This can be an abnormality found within the walls, valves, or blood vessels of the heart.

While congenital heart disease is, at times, life-threatening, this is not always the case. Some of those with congenital heart disease experience no symptoms or mild symptoms. It is, by no means, a death sentence. Living with CHD is possible.

However, more studies are needed to confirm congenital heart disease causes and its related risks.

If your condition falls under the category of heart valve defects, this means that the valves inside your heart either close up or leak. This causes problems in how blood flow is directed around your heart and your body. What happens is that the heart valves interfere with the correct pumping of blood.

What happens if you have a congenital heart defect?

If the problem with your heart lies with wall defects, this means that the natural wall between the left and right sides, or the upper and lower chambers of the heart, did not develop properly. This condition puts more pressure on the heart to function properly, and this could lead to high blood pressure.

With blood vessel defects, it is the arteries that are not functioning properly. This could lead to serious complications, because blood flow can be reduced or blocked.

Some of the signs of congenital heart disease are:

  • a bluish hue on the lips, fingers, toes, and skin of the baby
  • difficulty in feeding
  • low birth weight
  • delayed growth
  • chest pain
  • trouble breathing

How The Heart Works

To better understand the condition and congenital heart disease causes, it is important to learn how the heart works.

The heart is an organ with four hollow chambers: two on the left and two on the right. It needs both chambers to work together.

The right side moves blood to the lungs, so that the blood can pick up oxygen. Then the heart returns the blood to the left side where blood is pumped out to the rest of the body.

Congenital Heart Disease Causes

Currently, there is still no proven cause as to why the heart may not develop correctly during a pregnancy. For some, it could be due to changes in genes or chromosomes.

Congenital heart defects are also thought to potentially be caused by genetics. While there are numerous hypotheses that could explain the cause of congenital heart disease, more research is needed.


One possible reason for a baby to have congenital heart disease is that the particular heart defect may run in the family. The condition could be inherited from either side the mother or father. If someone in the family has congenital heart disease, it is possible that a baby born into that family will also have congenital heart disease.

Alcohol Consumption or Illegal Drugs

If a pregnant woman takes certain medication, drinks alcohol, or uses illegal drugs during her pregnancy, the baby is at a higher risk of developing congenital heart disease. This is not always the case, but there is a relationship between drug use and congenital heart disease.

Further research is still needed to validate this.

Certain medications

Certain medicines are associated with an increase in the risk of congenital heart defects. These include ACE inhibitors, lithium, statins, acne medication, and Thalomid. Though not yet proven, it is best to avoid these during pregnancy and to always consult your doctor before taking any medication during pregnancy.

In addition to congenital heart disease causes, there are certain risk factors that increase the chances of congenital heart disease.

Risk Factors

Viral infection

If a pregnant woman suffers from a viral infection within the first three months of her pregnancy, it increases the possibility that the child born will have a heart defect. Getting a viral infection during the first trimester can be harmful to the development of the baby’s vital organs.


If you contract Rubella, also known as German Measles, while pregnant, there’s a possibility that it can interfere with the development of your baby’s heart. If you are planning on getting pregnant, it is best to have your doctor test you for immunity to measles and other diseases, or you can get a vaccine before you conceive.

How heart defects develop

The heart develops during the 6th week of pregnancy. At this time, the major blood vessels begin to form. This is very important because these blood vessels will be responsible for ensuring proper blood flow in your child’s body.

If a baby will develop congenital heart disease, it is at this point that the defects may develop. As mentioned earlier, it is still unknown what exactly causes defects, but it is usually within this period that the defects start to manifest. More research is needed to confirm congenital heart disease causes and how these can be prevented.

Key Takeaways

Though there are no congenital heart disease causes that have been scientifically proven, it is best to avoid potential risk factors to ensure a healthy pregnancy.

Since the first trimester is the stage where all of the internal organs develop in a baby, it is best to avoid smoking, alcohol, illegal drugs, and prescription medication to minimize the possibility of any defects.

It is also recommended to be extra vigilant against viral diseases, as these can increase the risk of congenital heart defects.

Remember that, with the improvement of medical treatment over the past years, many babies who have congenital heart defects are able to lead long, healthy lives. The right treatment and medical care is key.

Hello Health Group does not provide medical advice, diagnosis or treatment.

Congenital Heart Defects in Children https://www.mayoclinic.org/diseases-conditions/congenital-heart-defects-children/symptoms-causes/syc-20350074 Accessed 8 June 2020 Congenital Heart Defects (CHD) https://www.cdc.gov/ncbddd/heartdefects/facts.html Accessed 8 June 2020 Living with a CHD https://www.cdc.gov/ncbddd/heartdefects/living.html Accessed 8 June 2020
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Written by Kathy Kenny Ylaya Ngo Updated Jun 08, 2020
Medically reviewed by Mike-Kenneth Go Doratan, M.D.