The only "legality" I can think that this OB was concerned about was his
malpractice insurance policy.  And I don't even think he can possibly be
interpreting that correctly.  A breastfeeding couple is just as much a
unit as a pregnant woman and a fetus, IMHO, and I just don't see how he
can treat one without treating the other.  By recommending weaning, he is
prescribing formula for that baby, so he really isn't avoiding liability
that way, especially where the known risks of formula are much greater
than the risks of the medication he has prescribed for the mother.

Rachael Hamlet