I have 2 grandbabies in NICU at present. My son asked the nurses what the "rules" were, what size is best, etc. They preferred a quilt about 30+ inches X 40+ inches. Large enough for top of the isolette, plus draping down the sides to protect baby from noise and light. Our quilts are labeled and are sent home with family to launder (in hot water). Those quilts that belong to the NICU are used on different babies, sent through the hospital laundry, and returned to the unit. They are not sent home with the babies. They like to have a darker color on the back to dim the light inside, and definitely batting inside the quilt. I would ask the nurses, they are the best resource for what works best in that particular NICU. Congratulations and prayers for the babies!