Ruth Cummings is with The Birth Center Milk Bank in Sacramento.

"For the last three or four months our donation rate has been down."

The non-profit collects donated breast milk for Prolacta, a product sold for-profit and prescribed to high-risk babies to help fight against infection.

Milk banks throughout the country are complaining of shortages. One possible reason is the increase in breast milk exchanges on the internet. Some moms are also selling their milk online.

Demand went up earlier this year after the U.S. Surgeon General released a report titled "Call to Action to Support Breastfeeding."

Meanwhile, Cummings says there should be no shortage of eligible donors.

"Women still don't know there's a way to donate. I'm sure that there's still human milk that goes down the drain all the time which is really hard to think about."

Hard to think about, she says, when you know the value of mother's milk.