Question: We have an ob patient who was just diagnosed with a heart murmur. The doctor is scheduling for her to have a fetal echo on the baby. What dx code would you use? Should I use O99.41-? Wyoming Subscriber Answer: No. Code O99.41-(Diseases of the circulatory system complicating pregnancy, by trimester) would not be correct because a heart murmur NOS (R01.0, Benign and innocent cardiac murmurs (includes functional heart murmur, or R01.1, Cardiac murmur, unspecified (includes heart murmur NOS)) would be considered a symptom, not a definitive diagnosis for heart disease. Instead, you would have to look up the exact “other” condition in the ICD-10 index to see if there is a comparable code, or go back to the ob-gyn for more information about the nature of the murmur. A heart murmur is classified as a symptom, not a disease until you find the source. Some murmurs are functional, meaning they cause no issues to the patient at all; just come and go.