This happens in the episode to where Darlene and David finally get to bring home thier baby. Before they come home, Dan and Roseanne are getting things ready. Dan walks in the back door into the kitchen with a box of diapers. If you look closely the diaper size is size 4, which is for 22 - 37 lbs. I dont think the baby gained this much weight in the hospital, especially with being a premie.