Captopril's absorption is significantly decreased by the presence of
food in the stomach, apparently by as much as 40%.  Obviously the baby
will always get it with food.  Captopril would appear in the milk in
only tiny amounts.  Baby's are often treated with captopril.  Personally
I would not worry about it.

Methyldopa, I believe, is mainly metabolized in the liver, so the renal
disease is probably not relevant.

I do not understand why pumping or breastfeeding would increase renal
solute load for the mother.

Not breastfeed has significant side effects for both mother and baby.
The risk of diabetes in the child is increased.

I would encourage this mother to breastfeed for no other reason for the
empowering effect of successful breastfeeding.

Jack Newman, MD, FRCPC