I was in the same situation with both my kids.

With DD, my fundal height was down from the beginning and DD was born at 2.98kg

DS, things were spot on until 30 weeks where things slowed heaps and was sent for a heap of U/S which showed bub was in the 5th percentile. I was induced at 40 weeks and DS was born weighing 2.66kg. The IUGR term was thrown around both before and after DS's birth.

If your DS was small then this one might just be too. Good luck, hope it all works out