Ultrasound estimated weight went down.

Allison • 💙6/6/16 👶🏻8/7/18
Hiya. Just came back from an ultra sound and baby's weight went down from 35 to 36 weeks. It was only by an ounce but I had expected an increase not the weight to stay the same. I won't hear back from the doctor until tomorrow. So I was just curious if this was normal occurrence? I've tried googling but all the results are about loosing pregnancy baby weight