Measuring a bit small at 36 weeks.

Since about 28 weeks at each of my appointments it’s kind of gone back and forth on if I’m measuring small or not. I go between seeing the dr and the midwife since it’s a collaborative practice. None of them have said it’s a problem or anything to be worried about. I went today and they said I was still a bit small and they want to do a growth scan. Is this anything I should be worried about? Has anyone else had experience with this?