Actually, prednisone is one of the drugs which is not necessarily okay
during breastfeeding just because it is okay during pregnancy.  That is
because it apparently does *not* cross the placenta.  However, prednisone is
generally safe during lactation because only very small amounts get into the
milk.  Hardly a concern for the baby.  If you look in Hale, he states that
data suggest that when a mother is taking 120 mg of prednisone/day the baby
would be getting about 47 micrograms/day.  Doses of 80 mg/day in mothers
produce insignificant absorption infants (<0.1% of dose).

By the way, I would guess your patient is on 30 mg, not 3 mg/day.

Jack Newman, MD, FRCPC