When I googled it I found this website and thought they would be perfect, not to mention simple to make. It reminded me of the Boo Boo Bear ice pack I made for the kids.
I made mine out of the softest flannel I had in my stash and rice I had in my pantry. The tutorial said to make them 6inches but that seemed huge to me so I did mine 5inches and used a bowl as a pattern.
I used a water soluble quilting pen to make the 1 inch circle in the center and stitched around it. You can see the blue markings in this pic:
A damp cloth wiped over the markings erases them.
They were really easy and quick to make so I figure if they work great I can make a couple more to always have a set in the freezer.
If you know of someone who is pregnant and going to be breastfeeding these would be great in a breastfeeding gift basket or along with a baby shower gift, or even with the gift your taking to the hospital after the baby's born.