I have heard many story's of women breast feeding with nipple rings. As long as they have compleatly healed, it is fine.You would have to make sure you keep them extra clean.

Some women take them out to nurse, and some leave them in. Personally I would remove them to nurse, I would fear them coming off and the baby chocking on them. To take them out each time you nurse would be a lot of hassle as new babies nurse for about a half an hour each side and nurse every other hour for the first few months, at least mine did.

I do not have my nipples pierced, but would like too. The above information is base on things I have heard and read.