Learning that your newborn has a heart murmur can be scary news. But heart murmurs in newborns are actually extremely common and often harmless.
Read on to learn more about what to look out for if your baby has a heart murmur.
Blood flows through the four chambers of the heart. Blood goes through different heart valves and circulates throughout the body via blood vessels before it returns to the heart and starts the process over again.
A typical heartbeat makes a “lub-dub” sound, which is caused by the heart valves closing. Heart murmurs are abnormal sounds (like whooshing, rasping, or swishing) caused by irregular blood flow. The sounds are heard between the regular beats, or changes in the beats themselves.
Murmurs can occur from something as simple as blood moving too fast, or from a structural issue with the heart.
Heart murmurs in children are very common and often go away on their own. However, it’s important to follow up with a pediatric cardiologist if your newborn has received a heart murmur diagnosis. Some heart murmurs may indicate an underlying condition that needs monitoring or treatment.
Heart murmurs in newborns and children are common. A 2022 study found that up to 8.6% of infants and 80% of children have a heart murmur.
There are two classifications of heart murmurs:
Innocent heart murmur
Also called physiologic murmurs, this type of murmur is found in both children and adults. It’s very common in healthy infants, children, and teens.
Most of the time, murmurs disappear when the child reaches adulthood, and they don’t require any treatment. A 2018 study found that less than
Here’s a general outline of the four types of innocent heart murmurs:
Pulmonary flow murmur or peripheral pulmonary stenosis (PPS)
Typically heard at 1 to 2 months of age, PPS occurs when a baby is born with small pulmonary blood vessels. Pulmonary blood vessels lead to the lungs.
Most PPS cases go away as the child grows. However, since PPS may also be associated with congenital heart disease, it’s important to continue care with your pediatrician and pediatric cardiologist, if appropriate, as your child grows.
Supraclavicular systemic flow murmur
This murmur is thought to arise from the typical fast flow of blood from the aorta, the largest artery in the body, into head and neck blood vessels.
Described as a low, harp-like hum, this murmur typically occurs in children ages 3 to 6 years, but can occur in adults and infants as well. Experts believe it’s caused by fibers that develop in the left ventricle and vibrate as blood flows through the heart.
This murmur is continuous and has a low pitch. It’s usually heard around the neck of the newborn. This murmur comes from the typical speedy return of blood to the heart through veins.
Abnormal heart murmur
A structural issue in a child’s heart can cause an abnormal heart murmur in a newborn or child. Examples include:
- a blocked valve (the structures between each chamber of the heart that open and close to facilitate blood flow)
- a hole in the heart, like with ventricular septal defect and atrial septal defect
In the case of a structural issue, a child’s murmur may be a sign of congenital heart disease.
Some types of abnormal heart murmurs may include:
Valve stenosis murmurs
These murmurs are created when a valve cannot open enough, and blood must jet past at a high speed.
These murmurs happen when blood pushes back in the wrong direction of blood flow, causing the incompetent valve to vibrate.
Murmurs related to narrowing or holes in the heart
These murmurs arise as blood moves at high speeds through a small pathway, occasionally in the wrong direction
The symptoms of a newborn heart murmur vary greatly depending on whether the murmur is innocent or abnormal, and whether there is a structural issue causing the murmur.
Most newborns with heart murmurs have no symptoms. A few heart murmurs associated with structural issues can cause recognizable symptoms.
In innocent heart murmurs, children remain asymptomatic while the murmur slowly disappears. However, pathologic abnormal murmurs can cause symptoms, including:
The causes of a newborn heart murmur depend greatly on the type of murmur.
Innocent heart murmurs
Innocent heart murmurs are
As your baby grows, so will these blood vessels. Innocent murmurs caused by these small vessels will typically go away on their own.
Your baby may also develop a murmur if they are sick or develop anemia. In both situations, the body needs to deliver oxygen via blood quickly, causing an increase in blood flow. This can potentially lead to a murmur simply from the increased speed of the blood.
Abnormal heart murmurs
Abnormal heart murmurs are more complex. Structural issues within the heart cause them. For example:
- Stenosis: This happens when a valve of the heart does not open properly, causing resistance to blood flow. Examples include mitral valve stenosis and aortic stenosis.
- Regurgitation: When a valve of the heart is not able to prevent the backward flow of blood, it allows blood to move in the wrong direction in the heart.
- Vessel outflow/tract narrowing: This narrowing of vessels or blood flow tracts creates greater resistance to blood flow and requires blood to move faster.
- Ventricular septal defect and atrial septal defect: In these conditions, different holes in the heart allow blood to flow between heart chambers that shouldn’t occur normally.
If your newborn has an abnormal heart murmur, it’s important to continue their care with a pediatrician and a pediatric cardiologist.
A doctor can diagnose murmurs by listening to your child’s heart with a stethoscope.
Murmurs are graded from 1 to 6 depending on how loud the sound is. Grade 1 is very faint and grade 6 is very loud, loud enough to hear without a stethoscope. Sometimes you can even feel the abnormal blood flow on the chest.
When your pediatrician hears a heart murmur, there are
In some cases, your doctor may also order an electrocardiogram. This test measures your heart’s electric activity. They may order a chest X-ray, too.
Your pediatrician and pediatric cardiologist will know the best steps for you and your child to get a quick and accurate diagnosis.
Treatment depends on the type of murmur.
Because innocent murmurs are not related to structural issues in the heart, an innocent murmur often resolves on its own. Your pediatrician and pediatric cardiologist will continue to monitor the murmur during your child’s annual checkups.
The treatment of abnormal heart murmurs can be complex. It will depend on the type and severity of the murmur.
There are times when structural heart issues can resolve on their own, so your doctor may recommend monitoring the situation before taking steps to treat the murmur.
However, if the murmur poses a risk to your child’s health, surgery might be necessary to treat the underlying heart disease or condition that’s causing the murmur.
You and your pediatric healthcare team will discuss all the options and can answer any questions you may have.
There are several
- family history of congenital heart disease
- maternal diabetes
- high blood pressure
- exposure to tobacco smoke in the womb
- exposure to certain medications in the womb
- maternal rubella infection while pregnant
If you’re concerned about these risk factors, talk with your doctor or OB-GYN during pregnancy or before becoming pregnant. Together, you can discuss what you can do to minimize your child’s risk.
The outlook for newborns who have an innocent heart murmur is generally quite positive. Almost all children with innocent heart murmurs live healthy lives and may grow out of their murmur.
Infants whose murmur is from congenital heart disease also generally have good outlooks, but there is a greater chance of
If your child has any type of congenital heart disease, it is important to talk with your pediatrician about your unique situation.
If my child does not have a murmur, does that mean they don’t have any problems with their heart?
The absence of a murmur alone does not guarantee a completely healthy infant heart. Some murmurs appear later in childhood, while other congenital heart diseases do not produce a murmur.
Because of this, it’s always important to schedule regular checkups with your pediatrician to monitor your baby’s heart health.
What happens if an abnormal pathologic heart murmur is not treated?
Initially, a child’s healthy heart and lungs can often overcome the stress associated with congenital heart disease. However, after an extended period, a child may begin to have complications from their murmur.
Abnormal blood flow creating the murmur can cause abnormal pressure in the heart chambers, leading to heart exhaustion and changes to the heart and lungs themselves.
Are louder or softer heart murmurs better?
It depends on the type of murmur.
In cases of holes in the heart, louder murmurs indicate smaller hole sizes, as blood has a harder time flowing through the narrow pathway. Meanwhile, for other conditions, a softer murmur may indicate decreased blood circulation.
Newborn heart murmurs are very common. They may be innocent or abnormal due to structural issues with the heart.
While it’s important to recognize that most newborn murmurs are innocent, it is still critical to follow up with your pediatrician to ensure the murmur is thoroughly evaluated.
If your child does have a murmur, they may need imaging tests to look at the heart. Depending on imaging test results, your child may need annual checkups or interventions, such as surgery.
In all cases, your pediatrician is central to helping correctly diagnose your child’s condition and to manage it in the best way possible.