I wouldn't use metallic for a baby quilt as there is that whole controversy about synthetic fibers melting. You'll also want to check with the manufacturer's website to make sure that the thread can be dried at least on low heat as children's quilts need to be laundered more frequently than adults. Personally, I have found that at least some metallic threads are more fragile than cotton & will snap more easily so I would want to do a practice piece & put it through the wash a couple times to make sure it will hold up to regular use.