(HealthDay News) -- Some babies are born with a heart murmur, which is a noise that blood makes as it flows through the heart. Most often, heart murmurs are considered harmless, says the American Academy of Family Physicians.

A murmur is sometimes called innocent, and is only noticeable because a child's heart is close to the wall of the chest, the academy explains. As a child grows, a murmur may become more difficult to hear, and it probably will disappear eventually. The majority of children with a murmur don't need to restrict activities or take any medication.

But any murmur should be evaluated by a doctor, since it sometimes indicates a serious problem, such as a hole in the heart, a leak or narrowing of a valve in the heart.

Doctors can perform tests to determine if a murmur indicates a problem or if it is harmless, the academy says.