My 2nd and 3rd pregnancies I thought I looked heaps huge compared to my first, my last pregnancy (4th) I always measured 7 weeks ahead from 21 weeks on wards but I never got any comments about my size, which I thought was werid, I got one man 3 days before I was due ask me how long I had left and when I said I had 3 days he said "wow I would have thought you had a few months!"

I think people comment on size because they are trying to interact with you, trying to start a convo maybe?