When Ms. S had her visit there, she was given a tiny ribbed hat like this pink one on Mr. Blue (the bear). This shape was great because it was very forgiving of different sized babies and could be rolled up as needed. This round of hats are on the large size, since they had very few that could fit a 7 lb baby. The small ones would fit a slightly smaller baby though.
These are super addictive to make since they go so quickly. And they are a great use for even scraps of nice acrylic. It is important that they be made of something that can be washed and dried on hot for the hospital's use. Most of these are in "boy" colors, but I can see myself making a bunch more in other colors.