This is not that rare and the problem presents exactly as you
describe.  Bilateral bleeding which sometimes begins during pregnancy,
and then usually settles by the end of the first week postpartum.  If
that's what it does, don't worry about the bleeding.

As far as the baby's refusing the breast for this reason, I haven't
seen that before and I would guess the refusal is the same as any
other refusal--poor latch.  Dehydration occurring in the presence of
so much milk coming out, blood tinged or not, means the baby just was
not getting on well enough to get the milk.  But I also doubt the
diagnosis.  What on earth is so bad about a serum sodium of 155 at 4
days?  From the information you give, I think it probably not
necessary to have admitted this baby to hospital.  Feed the baby,
that's all that was necessary.  Sure, the baby tends to spit up more
if there's blood in the milk, but if he gets the milk, he'll still
keep lots down.

Jack Newman, MD, FRCPC