My twin granddaughters headed straight to the NICU when they were born at 33 weeks. As others said, ask the nurses what they use. If they say nothing, respect it and make things for when the baby comes home. As a thank-you gift, I started working with a group called The Preemie Project in Iowa. You can google them for more information. They support a number of NICUs, and they have good patterns and advice.