Measuring small at 31 weeks

[MyBreadIsEggy]

I'm just back from my midwife appointment, and she says my bump is measuring small, and sure enough, there has been a drop on the line they plot measurements on. She says she wants to check again in 2 weeks instead of 3, and if it's still dropped down, then send me for a growth scan?
Now I understand that, but with my last pregnancy, I measured 2-3cm smaller than expected at every appointment and there was no talk of extra scans etc, and Dd was born 2 weeks early, 5lbs 15oz - small but perfectly healthy. I'm also quite a petite person, so surely that would be taken into account too before I have to go and have more scans and checks?

it'll be because of the drop on the line and not the size. If you consistently measured on the same track then they probably wouldn't scan. Generally you would need three points on a graph to ascertain if there is a pattern or not. I have been getting extra growth scans this time round as my DC1 stopped growing at 39 weeks. I have had a drop from 75th centile to 20-30th centile and am getting scanned every two weeks as a precaution, although my last two scans plotted on the same line.

That explains why I didn't have any growth scans last time then - I was consistently smaller than expected, whereas this time there has been a drop on the line.