What is an s3 heart murmur ? how serious is it? 38 year old woman asymptomatic. had a baby one year ago

S3 : S3 is the description used for a 3rd heart sound after the typical "lub dub" you hear when listening to the heart. Young people, athletes, and pregnant women often have an s3 on exam and it is considered completely normal. It can also be an indicator of congestive heart failure, but patients often have other symptoms such as shortness of breath with exercise or lying down, fatigue, swelling of extremeties, weight gain and fluid retention, and coughing up pink phlegm. Since she is 38, asymptomatic, and recently had a child, it is likely benign. If she starts to notice any of the symptoms above, she should call her doctor right away.