31 week growth scan

I went for mine today and they said babies went from 32nd and 34th percentile to now only being in the 12th and 14th percentile. The dr wasn’t happy with those rates and moved me to weekly appointments and bpp tests and says we will do another growth scan in 3 weeks to see if they have fallen below the 10 percent mark. My question is, if they have fallen below the 10th percentile what will they do about it? Anyone experience this, any advice would be appreciated!