With my DS, I had a 3 trimester scan at 36w4d because I was measuring big so it was more of a growth scan (which I get a kick out of since they can be wrong +/- 2 lbs at that point but I got to see baby so whatever and it ended up being about right on because I went in to labor 3 days later and it was pretty close). This pregnancy I have GD and am anticipating more scans along with NST from what I've read. I see my doctor tomorrow and will find out more about what the timing is for this. I think there are a lot of providers that will do one routinely and call it a growth scan, while others only do it if medically indicated. I'm all for the extra monitoring if medically necessary and if it enables baby to cook longer.