This will certainly be obvious to many but I know from experience in
teaching test weighing to hospital staff that it will not be obvious to
another equally intelligent subset of practitioners so please, no one
be offended.

If you are slipping in a sneak test weight, so as to avoid unnerving
the mom, remember that ALL things must be equal during pre and post
weights.  That means the same diaper or clothing or lack there of.  If
the baby is nude and voids or stools or spits up during the feed the
test weight is invalid and will be too low.   Conversely, if mom leaks
onto baby clothing from opposite breast or if baby has a poor seal and
leaks milk onto the clothing then the post weight will be in error on
the too high side.

Also, don't let too much time pass between weights.  I don't have a
firm number for this and would be interested if anyone else does but as
time passesweight will be lost due to insensible losses.

I usually handle this by doing a nude pre-weight, diapering or dressing
the baby and "happening" to put the baby back down on the scale again
before the feeding.   Sometimes I clue the mom in, other times I don't.
It depends on my "reading" of her possible reactions to this tool as
pressure or reassurance.

Carla