My supervisor at the hospital, Alice, gave each of the lactation consultants this great teaching tool as a holiday gift.
They're called 'belly balls,' and each little ball represents the size of a newborn's stomach. The smallest (the size of a small marble) is for day 1 of life, the next is for day 3, and the largest (the size of a ping pong ball) is for day 10.
What this illustrates so well is that the small amount of colostrum that a mother makes before her mature milk comes in are just perfect for a baby in the first few days of life. Many women worry that they aren't producing enough to satisfy their babies, and this concern often leads to early supplementation with formula. These balls show that a newborn's stomach is just the right size for the amount of milk a mother makes during those first few days.
The write-up on the back of the package states: 
Researchers have found that on Day 1, the newborn's small stomach does not stretch to hold more, as it will even a day or two later. This explains the experience of countless hospital nurses who have learned the hard way that when newborns are fed an ounce or two by bottle during the first day of life, most of it tends to come right back up. The walls of the newborn stomach stay firm, expelling extra milk rather than stretching to hold it.
These belly balls are made by Hollister, a pump company, but you can make your own with a marble, a wooden bead or shooter marble, a ping pong ball, and a little organza bag. To the right is my homemade version. My friend Joanna, who works as a lactation consultant at Stanford Hospital, carries one like this around with her from room to room. How about making one as a stocking stuffer this year?
Please note that these balls can be a choking hazard, so make and use your set of belly balls with this in mind.
