Hi, my daughter is 21 weeks pregnant, recent test showed a small artery comin out @ the base of baby's heart & goin bak in again. is this a concern.?

This depends: On a full analysis of the baby's entire cardiac anatomy. If there is a suspicion of a significant cardiac abnormality, or there are other risk factors in the mother or family, a formal fetal echocardiogram should be performed. These are usually done at specialized children's hospitals. It sounds like more discussion is needed.

Question confusing: A babies heart can have some interesting abnormalities with a variety of outcomes.The description you gave doesn't fit anything i've ever heard of in three decades. Perhaps the early information you received was not clear. The test interpreter may either give a specific DX or recommend a higher level scan for more specific information.