All chemicals, like all drugs, get into the milk in only tiny amounts.
If the chemicals are fat soluble, they will be excreted into the milk
slowly over time, and the amounts will be tiny at each particular
feeding.  If they are water soluble, they will get into the milk more
slowly.

I would suggest she breastfeed, and not worry about this.

What on earth is someone doing sending a nursing, or non nursing, mother
into this stuff for anyway?  Surely someone else could do it, no?

Jack Newman, MD, FRCPC