To clear this up (even though I've blogged about it before)...
Tricia is unable to feed Gwyneth because of all of the meds she (Tricia) is on (and some other reasons).
Therefore, Gwyneth is eating donated preemie breast milk from mothers of other preemie babies. Don't ask me how it works...all I know is that I have been told, by the NICU people here at Duke, that there are about 9 "banks" in the US, and one is very close to Duke, which makes for easy access for the NICU here at Duke (many NICU's that are not near a bank have a difficult time obtaining donated milk from a bank). She eats milk that is appropriate for her age, and as she grows bigger and older, will be given different milk from mothers of babies of the same age/size.
You can read more about preemie breast milk Here.
That's all I have to say about that.