I would concur with Dr. Newmans' prior "musings". Transplacental transfer of drugs is significantly different (and generally more) when compared to the transfer of drugs in human milk. It appears far more difficult for drugs to enter milk than enter the fetus. It is apparent to me that the transfer of drugs into milk is about as difficult as the transfer through the Blood-Brain barrier, and most drugs have great difficulty in passing both of these barriers. I would surmise that nature provided this "safety factor" to protect the human infant (postpartum) from exogenous substances that mom may ingest. Isn't nature wonderful. Regards Tom Hale,PH.D.