I know some babes with heart problems have blue extremities
and some are obvious but some are not.  A babe I worked with
a few years ago was checked frequently by different peds and
the heart problem was not diagnosed until X-rays were done
at 6 weeks.  Babe was 7lbs at birth and 7lbs at six weeks and
mom had been pumping lots of hind milk and supplementing
with a tube at the breast almost all of that time.  This baby
also looked fine and no one would have guessed she was so
ill.  Heart problems are not always obvious unfortunately.

Hope this is not the case with your babe and all will be well soon.

Ruth Bacon   IBCLC  Thornhill Ontario