Atrial Septal Defect is a Heart Defect
Approximately 5 to 10 percent of babies born each year with a congenital heart defect have atrial septal defect (ASD), which affects the way blood flows through the heart. ASD affects girls twice as often as boys. (2)
A normal heart has two sides separated by a wall or septum. With ASD, there is a hole in this wall that allows oxygen-poor blood from the right side to mix with oxygen-rich blood from the left side.
Oxygen-rich blood gets pumped back to the lungs instead out to the body, and oxygen-poor blood gets pumped out to the body, with the heart and the lungs working twice as hard as they should be.
You can see a diagram of the difference between a normal heart and an atrial septal heart here.
Doctors and researchers don't know what causes these defects, nor are they able to provide definitive recommendations for what pregnant or trying-to-get-pregnant moms can do to prevent the risk of having a child with a congenital heart defect,. However, “[s]moking during pregnancy ... has been linked to several congenital heart defects, including septal defects.” (1)
Development of the Heart
The heart develops during the first eight weeks of gestation. Every baby is born with a hole between the upper heart chambers to allow blood to flow away from the lungs just before birth. Since the hole is no longer needed after birth, it eventually closes. (4) If this hole doesn’t completely close, it can pose a problem.
Symptoms and Treatment of ASD
Small openings do not usually produce any symptoms and treatment is not usually necessary.
A baby born with a large ASD, however, may present with symptoms (3) such as:
• Frequent respiratory or lung infections
• Difficulty breathing
• Tiring when feeding
• Shortness of breath during activity
• Skipped heartbeats or a sense of feeling the heartbeat
• A heart murmur (whooshing sound) heard through a stethoscope
• Swelling of legs, feet, or stomach area