I found this post in my files. This was from 1989. Hale's 2000 book should have assurances in it, along with references that the doctor can see, even if she/he chooses to not locate them. Pat Gima, IBCLC Milwaukee, Wisconsin To :Susan Re :Interferon Beta-1A( Avonex) Avonex is the beta 1A form of interferon. It is slightly different from the other forms of interferon but they all contain about 165 amino acids and are quite large in molecular weight. At present there are no published data on the transfer of interferons following clinical dosing in human breastmilk. We do know that breastmilk normally contains small amounts anyway. I can tell you that I have just finished a project measuring the transfer of interferon alpha into human milk following the administration of 30 million units IV per day for 5 days in one patient. In this patient, we found that interferon did not transfer into her milk even following these huge doses. Therefore, I feel confident in saying that it is very unlikely that any form of interferon will transfer into human milk in clinically relevant levels, it's simply too big. Regards Tom Hale, Ph.D. Mailto:[log in to unmask] *********************************************** The LACTNET mailing list is powered by L-Soft's renowned LISTSERV(R) list management software together with L-Soft's LSMTP(TM) mailer for lightning fast mail delivery. For more information, go to: http://www.lsoft.com/LISTSERV-powered.html