I am on IVIG for neuropathy. I asked my OB if I could breastfeed my son and he actually advised me against it. Apparently there are not enough studies saying that in the long run there wont be any negative side effects for him. Although I feel guilty about this, I would rather be safe than sorry. I hope this helps.
I am also getting an IVIG treatment in September. I have been told by doctors at the IU medical hospital neuro center that the IVIG won't hurt. But don't take my word for it - I'd keep asking. I also heard that getting the treatment can help with fertility and many get pregnant on it.