You would need 0-3 Month clothes. You can get newborn as well. But they don't last long. He will grow out of them In a week.
I also recommend googling a list for a hospital bag if your worried about bringing the wrong things.
The hospital should provide/give some stuff for you if you ask.
But here is what I would bring:
- 3 sets of 0-3 Month clothes
- diapers and wipes (enough for changing once every 2 hours)
- a nuk, burp cloths, bibs
- formula or breast pump and 2 or 3 bottles (whichever is needed)
Bring a preemie size, they fit the best for newborns, of course it wont last long he will grow out of it but its great for the 2-3 days, especially if your gonna get pictures done and for the outfit home. You can bring a newborn outfit just in case. I had a 8 lbs and 4 oz boy and the newborn was still baggy on him.