A huge number of mothers of drug-addicted infants in the NICU choose to breast feed, because (and sorry lactation consultants, here is where I disagree with you) a lot more of the medication than I think they claim, makes it to the baby, therefore your Finnegan score is going to be lower, therefore, baby goes home sooner.
Mommy doesn't want a screamer on her hands just because the baby is home, so she keeps breastfeeding. I see the same thing happen with mothers who are heavy smokers...the babies calm down after they are breast fed because they get their nicotine fix.
I do not understand, how any research, can say that narcotics are less harmful than NOT breast breastfeeding. I know of one lactation consultant in a hospital system that if you test positive for drugs, you can do whatever you want with your baby when you get home, they will even freeze and store your breast milk for you, but you won't breast feed your baby while you are admitted.
With regards to the mother in the news story...I personally feel that if the baby had that much in her system, the mother gave it to her directly just to shut her up.