I don't know about writing this on the label, but someone posted the following poem which I saved on my computer. It would be a nice addition to a card maybe:
For the New Baby
This quilt of many colors was made with love and joy,
I hope it helps to welcome your precious girl or boy.
Use it during playtime or when they go to sleep,
Use it when you cuddle them, the chill away to keep.
Wrap this quilt around them when on an outing you go,
This quilt was given to be used, not just made for show.
And as mother, children can make a mess I know,
If the quilt gets dirty, in the washing machine it can go.
Author Unknown