IUGR??

has anyone been diagnosed with IUGR? At my 20 week scan she was measuring in the 6%. Went back at 24 weeks and she's still 6%. Consistent but small. I was wondering if anyone with it could explain to me their causes and what their doctors plan is for them. My doctor has me doing weekly US until 28 weeks then I will get 2x a week us and nst unless she jumps up to the 10% or higher