This is a normal occurrence IF:
baby is having at least 6 - 8 wet diapers daily
baby is not exhibiting outward discomfort

Most babies this age experience a growth spurt and will utilize every
component of breastmilk available.  There will be little waste which can
turn into stool.  Most babies will eventually have a BM, usually very
profuse.  The baby usually needs a bath.  I would worry only if baby
seems uncomfortable, or does NOT have enough wet diapers.  I've seen
this occur several times in this age bracket.  Keep us posted!  Lack of
stools seems to cause a lot of parental anxiety.

Heidi S. Roibal BS, LLLL, IBLCE
Child Development Specialist

"Always do right--this will gratify some and astonish the rest."
--Mark Twain