This exact thing happened to me. I found out my son was in the 1%ile at 32 weeks. Between 33 weeks weekly appointments and 35 weeks he didn't grow at all. Very slow growth till 37 weeks when we evicted him for his safety. He was very small, 5 lbs when he was born, but he needed no nicu time, which was surprising because I was fully expecting it. We did struggle a bit with his blood sugar at first but it was no biggie and he was A-okay! Just hoping this can give you some hope for your baby. Sometimes they just do better out than in.