Abdominal percentile

Hello

Just wondering if any of you have had been told baby's abdominal percentile is going down?

At 20 weeks his abdominal percentile was 57th, at 26 weeks it was 33rd and this week at 30 weeks it was 17th percentile.

I have to go back on 30th for another scan but I'm worried and feel like I have very information...I don't know if there's anything I should or shouldn't do in thr 2 weeks.

I also don't know if I need to be thinking about packing our hospital bag in case he still hasn't caught up?

Would appreciate your experiences x