Jay:  You've already gotten some good responses from Laurie Wheeler and
Jane Bradshaw, but I have something to add that may clarify some of the
issues in people with diabetes and kidney problems.  Although it's
possible that this mother already has kidney problems from her diabetes
even if asymptomatic, in which case Jane's comments are very germane and
prompt treatment may supersede considerations of continued breastfeeding,
it's also possible that she has been found on a screening test to be
spilling minute amounts of protein in her urine (a test known as
microalbuminuria).  If this is the case, it is a very early sign of the
kidneys being affected by the diabetes, but may be a long way from
full-blown kidney disease.  Often, this is amenable to tight control of
the blood sugars (which she may actually achieve easier while continuing
to breastfeed), and sometimes medications such as ACE inhibitors (e.g.
captopril or enalapril - trade names capoten and vasotec, both AAP
compatible with breastfeeding) are added.
Bottom line, if this is very early microalbuminuria, there is probably no
need to wean, even if ACE inhibitors are needed.  If there is more
serious kidney disease, the need to wean needs to be assessed in terms of
the specific medical situation.  Keep us posted as you get more details.
Alicia.  [log in to unmask]