Heart Murmur Detected at Birth
The short answer
Heart murmurs are very common in newborns and are often innocent (harmless). They are extra sounds heard with a stethoscope caused by blood flowing through the heart. Many murmurs detected at birth resolve on their own as the circulatory system transitions from fetal to newborn circulation. Your pediatrician may order an echocardiogram to confirm the murmur is innocent.
Parents everywhere have the same worry. You are doing the right thing by looking into it.
By Age
What to expect by age
Heart murmurs are heard in many newborns during the first few days. As your baby's circulatory system transitions from the fetal pattern (where the placenta provided oxygen) to the newborn pattern (where the lungs take over), temporary murmurs are common. Many are caused by a patent ductus arteriosus (PDA), which normally closes within the first few days. If a murmur persists, your doctor may order an echocardiogram (ultrasound of the heart) to evaluate. Most murmurs found in healthy, well-appearing newborns turn out to be innocent.
If an echocardiogram confirmed an innocent murmur or a small, hemodynamically insignificant finding (like a small PDA or PFO), reassurance and monitoring are all that is needed. If a structural heart defect was found, a pediatric cardiologist will guide management and follow-up.
Innocent murmurs may come and go. They may be louder during illness or fever and softer when baby is calm. This is expected. Follow-up for any identified structural abnormality continues as recommended.
Innocent murmurs can persist throughout childhood and have no health significance. They do not require activity restrictions or antibiotics for dental procedures. Murmurs associated with structural defects are managed per the cardiologist's recommendations.
What Should You Do?
When to take action
- An innocent murmur confirmed by echocardiogram in a well baby
- Baby is feeding well, gaining weight, breathing comfortably, and has good skin color
- The murmur becomes softer over time
- Pediatrician is not concerned after evaluation
- A new murmur is heard at any well-child visit
- You want to understand what the murmur means for your baby
- You have a family history of heart defects
- A murmur combined with difficulty feeding, rapid breathing, poor weight gain, or blue/gray skin color, which could indicate a significant heart defect
- Baby becomes lethargic, sweaty during feeds, or has persistent rapid breathing
Sources
Related Resources
Trust your instincts. If something feels wrong, reach out to your pediatrician.
Worrying about your baby means you care. That is a good thing.
Related Medical Concerns
Baby Heart Murmur - Innocent vs Concerning
Heart murmurs are very common in children - up to 75% of children will have an audible murmur at some point. The vast majority are "innocent" or "functional" murmurs, meaning there is no structural heart problem. These murmurs are simply the sound of blood flowing normally through the heart and are more audible during fever, illness, or excitement. A smaller number of murmurs indicate a structural heart difference that may need monitoring or treatment. Your pediatrician can usually distinguish between the two and will refer for an echocardiogram if there is any concern.
Congenital Heart Defect Signs in Babies
Congenital heart defects (CHDs) are the most common type of birth defect, affecting about 1 in 100 babies. They range from small holes in the heart that may close on their own to complex defects requiring multiple surgeries. Early detection through pulse oximetry screening and recognizing key signs — such as blue skin, rapid breathing, poor feeding, and failure to gain weight — is critical. Advances in surgery have dramatically improved survival and quality of life.
Patent Ductus Arteriosus (PDA) in Babies
Patent ductus arteriosus (PDA) occurs when the ductus arteriosus — a blood vessel that normally closes shortly after birth — remains open. It is very common in premature babies, occurring in about 60% of babies born before 28 weeks. In full-term babies, a PDA is less common but can occur. Small PDAs may close on their own. Larger PDAs can be closed with medication, catheter procedures, or surgery, with excellent outcomes.
My Baby's Head Shape Looks Abnormal
Many babies develop temporary head shape irregularities that are completely normal. A cone-shaped head from vaginal delivery reshapes within days. Mild positional flattening (plagiocephaly) from sleeping on the back is very common and usually improves with repositioning and tummy time. However, head shape changes involving ridges, a persistently bulging fontanelle, or rapid head growth changes should be evaluated to rule out craniosynostosis.
Achondroplasia (Dwarfism) in Babies
Achondroplasia is the most common form of short-limbed dwarfism, affecting about 1 in 15,000 to 40,000 births. It is caused by a mutation in the FGFR3 gene and is usually apparent at birth with characteristic features including short limbs, a larger head, and a prominent forehead. Intelligence is normal. With monitoring for specific complications and supportive care, children with achondroplasia lead full, active, and independent lives.
Adenoid Hypertrophy and Breathing
Adenoids are lymphoid tissue located behind the nose that help fight infection in young children. When adenoids become enlarged (adenoid hypertrophy), they can block the nasal airway, causing chronic mouth breathing, snoring, nasal speech, and sleep-disordered breathing. Enlarged adenoids are most common between ages 2-7 and are a leading cause of obstructive sleep apnea in young children. Treatment ranges from watchful waiting and nasal steroids to surgical removal (adenoidectomy) if breathing or sleep is significantly affected.