A heart murmur is an extra sound that the blood makes as it flows through the heart. Your doctor uses a stethoscope to listen to your heartbeat. When you have a heart murmur, your doctor can hear an extra whooshing or swishing noise along with your heartbeat.

It can be scary to learn that you or your child has a heart murmur. But heart murmurs are very common, especially in children, and are usually harmless. These normal murmurs are called "innocent" heart murmurs. There is nothing wrong with your heart when you have an innocent murmur. Up to half of all children have innocent murmurs. They usually go away as children grow.

Adults can have innocent murmurs too. Innocent murmurs are often found in adults over 50 years of age. Murmurs also happen when your blood flows harder and faster than usual—during pregnancy, for example, or a temporary illness, such as a fever.

Sometimes, though, a heart murmur is a sign of a heart problem. This is called an abnormal heart murmur.