Kate Risingsun manages the lactation program at Sutter Medical Center in Sacramento. She says Sutter buys breast milk from a milk bank to feed premature babies in the neo-natal intensive care unit:

Risingsun: "It's mostly for these very medically vulnerable babies who we use the banked milk for, because there really is a shortage." 

Risingsun says preemies are especially vulnerable to a severe gut infection and when they're fed breast milk, the rate of infection goes down dramatically.  She says some moms of premature babies are ill themselves and unable to get their milk supply going:

Risingsun: "Because a mother isn't able to produce milk for whatever reason, that shouldn't be a reason why a baby shouldn't get this really important protection."