I’m 28 weeks and four days I just left my appointment they said my sons measuring a week under then what I should be and it could be because my iron came back a little low and said in 2 weeks they would check my iron again and measurements and if it was the same they would do an ultrasound has anyone else gone through this?
The Dr’s said the cause is low iron? I have low iron as well but my baby is measuring 2 days ahead. I have raised it by taking a extra iron supplement on top of my 1 iron pill and prenatal and ask then if that is a good option for you. I know there are foods high I’m iron. But I’m the lucky one at 34 weeks I will throw up from that food 
but also some babies do just measure small but are still healthy 
My third baby always measured small I had him at 37 weeks he was 5lbs13oz 21 1/2 in long so that tells me measuring is not accurate because 21 and half inches is a long baby so I would worry unless they do an ultrasound and find something to worry about