White spot in baby's heart!

Mindy • Mom of 2 yr old boy and baby girl due 8/31/17
Went in for my 20 week anatomy scan today and the Dr. told me they found a white spot in my daughters heart.She said it could be a soft marker for down syndrome.She said I'm very low risk and everything else was normal and there were no other indicators of DS.They apperantly see it so often that she felt silly telling me.However she did recommend I have blood work done,just to rule it out completely and she didn't really seem concerned.Of course me being the worry wart that I am,I'm having major anxiety over this.Has this happened to anyone else?I won't have my results back for another 2 weeks.