I know the 10th percentile is different for every mum/baby but just out of curiosity!? I'm also aware that growth scans can be wildly inaccurate 
This wasn't something I experienced with my first, who was 7lbs 9 @ 39 weeks.
I am TINY this time around, @ almost 32 weeks... feels very alien & I am concerned but the midwife's/sonographers etc seem happy.