I do not understand why testing positive for ketones would require the
mother to stop breastfeeding.  A child who vomits twice sometimes has
ketones in the urine (not from diabetes obviously).  Why would ketones
be harmful to a baby?  Indeed, ketones may be used by the neonatal brain
for energy when the baby is hypoglycemic.

Ketones often persist in the urine for many hours, sometimes a few days
after a diabetic's blood sugar is under control.  In my opinion, I think
it is perfectly acceptable for the mother to breastfeed, and the ketones
in the urine should be ignored for this purpose.

Breastfeeding is too important to sacrifice just because.  I have loaned
out my Lawrence so I am not sure what she says, but I have my doubts
that the reason is compelling.

Jack Newman, MD, FRCPC