I did both in the same day. They get a sugar high but then crash, just like we do lol. So I would be more worried about baby not moving to help with pictures. The ultrasound techs are really good though
I took the test 3 times (Hopefully it doesn't make you sick) and every time I took it he was really active right after, but then showed down a lot towards the end of the test. Like to the point where I got pretty worried. But I asked the doc and she said sometimes they get a sugar high and then a sugar crash.
I'm only 21 weeks but baby is always active and we have gotten great pictures. They always think I've had sugar before my appointment but baby just likes to move a lot!