There are two issues: likelihood (risk of) aspiration, and risks due to 
having aspirated.

Mizuno, Katsumi. Effects of Different Fluids on the Relationship Between 
Swallowing and Breathing During Nutritive Sucking in Neonates. Biol 
Neonate 81, no. 1 (January 2002): 45-50.

That one is on bottle feeding, but he found that babies swallowed in a 
safer part of the suck:swallow:breathe cycle when there was human milk 
in the bottle vs. artificial milk or water.

The risk from aspiration is likely less from human milk, because it is 
not a foreign protein, so there is less risk of chemical pneumonia. 
There are no studies that "prove" this, but the studies that show 
irritation from aspiration were done in RABBITS. Yes, human milk is NOT 
species specific for rabbits.  There are also some autopsy studies that 
found some human milk protein in the lung tissue of newborns and older 
babies who died  after bottle feeding human milk, which is suggestive of 
but not proof that the milk was aspirated and may have led to asphyxiation.

             ***********************************************

To temporarily stop your subscription: set lactnet nomail
To start it again: set lactnet mail (or digest)
To unsubscribe: unsubscribe lactnet
All commands go to [log in to unmask]

The LACTNET email list is powered by LISTSERV (R).
There is only one LISTSERV. To learn more, visit:
http://www.lsoft.com/LISTSERV-powered.html