I have one mother with systemic lupus who is breastfeeding, and aside
from sore nipples, for which she came to see me (probably from Candida
as she is on prednisone), is doing very well.  The baby is also doing
well.

I think it is extremely unlikely that the mother could pass something
on in her milk which could cause the baby to have symptoms or develop
lupus.

There is not much done on this from the point of view of research.  I
would reassure the mother, and I think you are right to tell her that,
if anything, breastfeeding probably protects.  As a pediatrician, I
have never seen a child with lupus at this age.  A newborn can get
heart block from a mother with lupus, but this develops in utero.

Jack Newman, MD, FRCPC