I have found a source for Mamivac nipple shields that are made in Germany.  They come in 3 sizes, and either conical or cherry shaped--where the nipple are a bit shorter and more rounded--which works really well for babies who seem to have trouble sensing the nipple and getting organized, or who have tongue-tie.   
Allowing the baby to come on and off the nipple shield with colotrum on the outside of it from the other breast, will let the baby become aquatinted with the different feel--never force the head on, let the baby control coming on and off, and that will prevent gagging, and make sure it is in the roof of the mouth.  If the nipple shield is not centered, the baby may not suck on it.  
I think this is the only resource for these in the United States.  I hope it alright to put here--don't want to deal with multiple inquiries.

Heidi Humphries,RN,BSN,IBCLC
Mother's Milk, inc/Spectra Baby USA
www.facebook.com/spectrababyusa
www.spectrababyusa.com

Thanks!
Kathleen Gale 
Chicago, IL

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