Preeme or newborn clothing

Nic

My son has Hydronephrosis grade 3. They are talking about possible delivery at 35 weeks due to him worsening. Today I am 34 weeks 2 days and he weighs 5 lbs 10 oz. I am not familiar with his because my previous son was born at 41 weeks 8 lbs 9 oz. Should I buy preemie or newborn clothing for him? What should I expect as far as NICU?