I have never in my experience come across the clinical scenario of
excessive sodium in breastmilk.  On the other hand I have found it
necessary to add sodium in large quantities to breastmilk when feeding very
low birthweight infants (who leak sodium rather readily from their
kidneys).  A healthy baby, and, in fact, most sick babies in intensive
care, can tolerate very high sodium intakes provide their kidneys are
healthy and they are not dehydrated.

To have "too much" sodium in breast milk seems improbable.  The sodium
content of milk may fluctuate, particularly as supply diminishes - we would
still not hesitate to use such a supply in a sick or premature infant.

Khalid

Khalid Aziz
Memorial University of Newfoundland